Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Mar Thu 21, 2019 6:58 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 37 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Zenith RD7000Y T/O project---radio bug bit again...
PostPosted: Jan Tue 22, 2019 3:27 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Hello All,

Man, as hard as I try to keep that "radio bug" in check, it still bites once in awhile when I don't want it too ! Especially at a perceived good deal on a desirable set...

I'm really out of room now for larger sets and had to shuffle several around in "designated" area to fit a smaller RCA cordless set on shelf... And there are only three sets left on the "seriously wanted list", so trying to be very careful while browsing Ebay...

But---when this very dusty RD7000Y "popped up" for $50 "Buy It Now" and the inside cosmetics looked to be in very nice shape, I couldn't resist hitting that "button" ! Guess I could clean it up and offer it in trade for the sets I'm seeking if I don't get too attached ???

Already downloaded the factory service manual and have read quite a bit here and elsewhere about some issues they may have and know several here have them, so hopefully won't be too difficult to get it into proper operation...

There always seems be a bunch of these on Ebay, so it's certainly not a hard to find radio...

Other than the additional features, how does performance & sound compare to the Royal 3000-1 ??? Will it be impressive enough to keep ?

John


Last edited by xrhonda91 on Jan Sat 26, 2019 6:56 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Tue 22, 2019 5:36 am 
Member

Joined: Apr Sat 16, 2011 2:25 am
Posts: 425
Location: Victor, MT USA
John, looks like got a good deal. Can't tell how it compares to a 3000 but its a keeper. You won't be getting rid of it...Alan

_________________
Don't worry about old age; it doesn't last that long.


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Tue 22, 2019 8:35 am 
Member

Joined: Aug Wed 24, 2011 4:35 am
Posts: 4292
Location: Sunnyvale CA
xrhonda91 wrote:
Hello All,

Man, as hard as I try to keep that "radio bug" in check, it still bites once in awhile when I don't want it too ! Especially at a perceived good deal on a desirable set...

I'm really out of room now for larger sets and had to shuffle several around in "designated" area to fit a smaller RCA cordless set on shelf... And there are only three sets left on the "seriously wanted list", so trying to be very careful while browsing Ebay...

But---when this very dusty RD7000Y "popped up" for $50 "Buy It Now" and the inside cosmetics looked to be in very nice shape, I couldn't resist hitting that "button" ! Guess I could clean it up and offer it in trade for the sets I'm seeking if I don't get too attached ???

Already downloaded the factory service manual and have read quite a bit here and elsewhere about some issues they may have and know several here have them, so hopefully won't be too difficult to get it into proper operation...

There always seems be a bunch of these on Ebay, so it's certainly not a hard to find radio...

Other than the additional features, how does performance & sound compare to the Royal 3000-1 ??? Will it be impressive enough to keep ?


It should sound substantially better than a 3000, and probably is more reliable (no tin whiskers...) . It's also something like 40 years old instead of 55. I think I have told everybody (to the point of annoyance, apparently) what I know about it, but:

The foam between the grill and case will have turned to dust over the years. Knowing how you go about things, you would have found this soon enough but all I usually do it get rid off all the foam debris that has accumulated at the bottom of the speaker opening. I assume that you can get super-thin foam rubber (or something acceptable as a substitute) from a car upholstery shop. Not removing the debris makes the speaker sound bad or the voice coil to rub in extreme cases. I haven't seen the same sort of problems with the grill rattling against the case that is common on the 1000 and 3000, but something moderately soft should go in there.

The case and mechanical bits are usual Zenith bizarro-world, although not as bad as the 1000/3000 in terms of random shims and unworkable mechanical bits. Of course the handle problem is solved (although the mechanism is typically elaborate), so no problems. The rusting bubbled chrome on top/sides is solved by not having any (brushed aluminum). There is occasionally a problem with the chrome-plated zinc side plates, but those are generally much better. The upholstery on the sides (thin vinyl with a foam pad) is prone to coming loose at the corners and is very prone to getting ripped. The Royal 7000 -1 and -2 solid rubber is much better, but as long as the pad isn't ripped, you can always glue it back down.

The chassis looks like an even more complicated 3000 with the same things in about the same places, and the VHF weather and voltage regulator added. Alignment is about the same sort of deal, straightforward but tedious. Ignore the VHF band adjustment. FM dial will be shifted to the left from the rest, twist all three slugs to get it back, maybe 3/4 a turn. Its surprising how consistent that drift is.

Tin whiskers aside, you have most of the same weak points as the 1000/3000. Clean the bandswitch the same way (lots of Deoxit). Recapping it is the most difficult of all the radios, some of the capacitors you need to replace are 1 mfd guys underneath the switch panel, and you can barely see them, much less get a soldering iron on them, without at least loosening the panel and lifting it up. Really, from a practical standpoint, desolder the wires along the bottom that keep the panel from flipping up, so you can open it up. Recap all the electrolytics and all the caps of any type associated with the tone control circuit (some of which which look like standard poly caps but for some reason are very frequently bad and will cause very "heavy" sound) while you were in there. Remove the dial drum to replace the capacitors under the drum. Mark the position of the drum with it on VHF, because there is a gear drive between the bandswitch shaft and the drum drive - it's not just drive directly by the shaft. Inspect the plastic gears on the drum for wear and damage. If the gear is worn, you can remove ends from the drum and swap them around, both ends have gears and the ones on the left end are not used and should be in good shape. Be careful with the drum plastic because it's brittle.

Recap the power supply on the back of the case, it's easy to get to. The voltage switch is usually fine and has usually never moved since it left the factory. The changeover switch is frequently intermittent and will come back if you run it back and forth a bunch of times.

The dial lights are usually a problem, and any of the three obvious weak areas could be to blame. On the bulb mount bus, find any place it counts on mechanical rivets or crimps to make electrical contact, and solder across the joint to ensure low resistance. Same with the terminal strip it connects to on the chassis (where they stuff a number of wires into a spring socket, and solder it - resolder any that seem suspect), and clean the switch and test it all before you put it back together. I have had some that never worked right no matter what I did. My inclination would be to replace it with the LEDs as shown last year and remove the 1.5V circuit entirely.

Troubleshooting is like any of the others, same sorts of issues but generally the 7000 is much less prone to problems with transistors and is generally more reliable. It's not beyond conception that a ceramic disk cap could fail, more likely than the others, but while respecting others experiences, it's not a widespread problem. It can be frustrating if you do have one, just because there are so many and you would normally never consider this a problem at all.

For as complex as it is (and it might be the most complex point-to-point wired radio ever made), it's not terrible to work on and I have not found any insurmountable problems.

You won't have any problems that you can't handle. And there is a reason that people hold the opinion that if you were only going to have one radio, this would be it.

Brett


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Tue 22, 2019 1:22 pm 
Member

Joined: Feb Thu 08, 2007 2:32 pm
Posts: 12373
Location: 06457
xrhonda91 wrote:
Hello All,

Man, as hard as I try to keep that "radio bug" in check, it still bites once in awhile when I don't want it too ! Especially at a perceived good deal on a desirable set...

I'm really out of room now for larger sets and had to shuffle several around in "designated" area to fit a smaller RCA cordless set on shelf... And there are only three sets left on the "seriously wanted list", so trying to be very careful while browsing Ebay...

But---when this very dusty RD7000Y "popped up" for $50 "Buy It Now" and the inside cosmetics looked to be in very nice shape, I couldn't resist hitting that "button" ! Guess I could clean it up and offer it in trade for the sets I'm seeking if I don't get too attached ???

Already downloaded the factory service manual and have read quite a bit here and elsewhere about some issues they may have and know several here have them, so hopefully won't be too difficult to get it into proper operation...

There always seems be a bunch of these on Ebay, so it's certainly not a hard to find radio...

Other than the additional features, how does performance & sound compare to the Royal 3000-1 ??? Will it be impressive enough to keep ?

John

How many years you been into storing radios???


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Tue 22, 2019 8:04 pm 
Member
User avatar

Joined: Aug Wed 26, 2009 1:50 am
Posts: 1449
Location: Mesquite NV 89027 (from Coventry, UK)
At $50 you can't go wrong. I have an earlier one, with the fixed weather band, and it is a good set. I haven't attempted to dismantle it yet, but probably will. Brett's detailed post will certainly help with that.

Colin


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Wed 23, 2019 1:46 am 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20188
Location: Utica, NY 13502 (USA)
hoffies2 wrote:
xrhonda91 wrote:
Hello All,

Man, as hard as I try to keep that "radio bug" in check, it still bites once in awhile when I don't want it too ! Especially at a perceived good deal on a desirable set...

I'm really out of room now for larger sets and had to shuffle several around in "designated" area to fit a smaller RCA cordless set on shelf... And there are only three sets left on the "seriously wanted list", so trying to be very careful while browsing Ebay...

But---when this very dusty RD7000Y "popped up" for $50 "Buy It Now" and the inside cosmetics looked to be in very nice shape, I couldn't resist hitting that "button" ! Guess I could clean it up and offer it in trade for the sets I'm seeking if I don't get too attached ???

Already downloaded the factory service manual and have read quite a bit here and elsewhere about some issues they may have and know several here have them, so hopefully won't be too difficult to get it into proper operation...

There always seems be a bunch of these on Ebay, so it's certainly not a hard to find radio...

Other than the additional features, how does performance & sound compare to the Royal 3000-1 ??? Will it be impressive enough to keep ?

John

How many years you been into storing radios???
That's baaad :twisted: :lol:

Dave


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Wed 23, 2019 3:58 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Thanks Guys !

Alan---you're probably right ! After spending several hours working on 'em, the bond grows strong...

Brett---really appreciate your informative discourse ! Always read your responses carefully to glean whatever I can from your experiences... A few things you've mentioned I've seen in other threads, but good to have it altogether here and glad you took the time to respond...

Hoffies2---Hmmm... Well, taking comment literally, entire collection is accessible and most on shelves in long shop-room closet (now crowded), few about house for ready use, and others in two display cabinets in family room. Only a couple junked parts sets are in a box in workbench cabinet. None are packed away and all but a couple refurbished and working... But I started hobby as a kid in 1970, quit mostly a couple years later but saved many of the radios, then got rid of most of those about 20 years ago, and started again after finding this site in 2009 while between jobs---and the last 10 years have been a real experience ! Have systematically moved non-radio items out of shop-room closet to guest bedroom closet to make room for more shelving---and am pretty much at limit now with what there is... Am kind of a "neat-freak" and sure don't want the house "cluttered"...

Colin---remember you mentioning that... What model/chassis is yours ?

Dave---yeah... What a difference a small mark of punctuation would make to that comment !

Hope to have time tomorrow to post the Ebay pics...

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Wed 23, 2019 4:27 am 
Member
User avatar

Joined: Aug Wed 26, 2009 1:50 am
Posts: 1449
Location: Mesquite NV 89027 (from Coventry, UK)
John,
Mine is a Royal 7000, chassis 18ZT40Z3


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Thu 24, 2019 1:59 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Is that the 1st Royal 7000 model, Colin ?

Here are the Ebay pics of mine---sure hope it cleans up well and has no unusual problems !

John


Attachments:
arf d7000y ebay1.jpg
arf d7000y ebay1.jpg [ 196.86 KiB | Viewed 706 times ]
arf d7000y ebay2.jpg
arf d7000y ebay2.jpg [ 215.23 KiB | Viewed 706 times ]
Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Thu 24, 2019 2:20 am 
Member

Joined: Aug Sat 16, 2014 2:19 am
Posts: 1239
Location: Palos Verdes, CA
John - I think you got a great deal on the Zenith RD7000Y as at $50, it was too good an opportunity to pass up! Sometimes on a "Buy Now" posting on eBay, it is worth taking some risk. Besides, I've found that of all the vintage transistor radios I've collected so far, the radios from Zenith have been the best. I'm currently listening to my Zenith Royal 900, which is all original ane performs like a new radio! - Mark


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Thu 24, 2019 3:05 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Thanks Mark !

Honestly don't have a place to keep it now and will have to see what else can be "shuffled" around to make room in the assigned radio spaces... Yes, the Zenith's are excellent radios and my "regular user" is a somewhat beat-up Royal 705 which is one of the best performers with very pleasant sound quality and precise vernier tuning...

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Thu 24, 2019 6:35 am 
Member
User avatar

Joined: Aug Wed 26, 2009 1:50 am
Posts: 1449
Location: Mesquite NV 89027 (from Coventry, UK)
xrhonda91 wrote:
Is that the 1st Royal 7000 model, Colin ?
John

I believe so, as it has a fixed weather band. The second iteration had plug in crystals to change the weather band, and yours should have a tuneable weather band.


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Fri 25, 2019 3:03 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Hey Colin---yes, this does have a tune-able weather band which works fine picking up our local station...

Hello All,

Received radio today and gave it preliminary cleaning. Pretty good condition except for scratching and small area of bubbled brushed chrome on top surface and minor pitting of other trim and bandswitch knob. Vinyl side panels fine. Battery compartment clean as described, but AC cord not right having a larger connector which wouldn't fit in cabinet opening and also designed for larger pins.

Really neat thing though, the seller checked in to see if radio arrived okay and told me he remembered his Dad buying it new---knowing that made it more valuable to me as I appreciate an item's history...

Installed batteries and it worked well on all bands even with antenna down with a couple SW and the VHF requiring a bit of rocking of bandswitch to come in. AM seemed really good, but it was night time. Volume and tone controls seem fine, but the RF gain is a bit erratic, but it appears to be a bad connection as even when turned off, receive dead until I wiggled knob (along with control) to bring it back on. Didn't try the BFO yet. Both dial-lights still work. Sound quality pretty much on par right now with the 3000, but doesn't seem muffled as described by some with the rotted foam problem.

More to come as project progresses !

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Fri 25, 2019 3:48 am 
Member

Joined: Aug Thu 23, 2018 1:11 pm
Posts: 28
Good cosmetics and $50, a real steal!

I've got both a 3000 and a D7000 and find the 7000 much "friendlier" to work on. Even getting the chassis out of the cabinet is easier for the 7000 than the 3000! Substitutes for the silicon transistors used in the 7000 are much more available than the germanium devices used in the 3000. I would judge the sensitivity of both radios comparable, at least on the broadcast band. Audio quality is also very similar, BTW I found that reducing the size of the ceramic capacitor at the base of the audio pre-driver transistor (TR15) brightens up the audio of the 7000, particularly on FM.

Be careful not to over-torque the chassis mounting screws on the 7000, they thread into plastic bosses in the cabinet and it is very easy to strip the threads out of the bosses. The cabinet of the 7000 is much less of a "tinker-toy" than the 3000

My particular D7000 had a bad trimmer in the local oscillator circuit which I had to replace, but occurrence of that failure mode seems to be rare. If you have trouble performing the oscillator stability adjustment as described in the service manual, check the trimpot!

Enjoy your find!

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Fri 25, 2019 2:06 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20188
Location: Utica, NY 13502 (USA)
joint46 wrote:
BTW I found that reducing the size of the ceramic capacitor at the base of the audio pre-driver transistor (TR15) brightens up the audio of the 7000, particularly on FM.
A complaint I have about almost every Zenith tube and transistor radio with FM that I've encountered is the lack of highs compared to many other brands. I once read somewhere that it was Zenith's philosophy that most people regard the sound of FM as being "tinny" or "scratchy" when the full audio range available from FM is reproduced, especially when compared with the narrow bandwidth of most AM sets.

Dave


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Sat 26, 2019 3:57 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Thanks much for info, John ! What value did you use to replace the .0033 uF disk ?

Radio is now working very well on all bands after just a bit of use and the AM BC band reception is noticeably better (sensitivity) than my Royal 1000D and 3000 and have not yet made any adjustments. The dial tracking is fine on all bands and the pointer is off slightly to left of tuned frequency due to being bent slightly that direction. And other than the erratic connection issue with RF gain control, it and all other functions work great---impressed by the amount of extra gain when RF control maxed in manual ! Listened to a few SSB QSO's and the BFO seemed very stable for the time I used it. The bandwidth selector also works well... Audio is clear with plenty of volume and control pots are noise-free. Even though band-switch is now doing good after a few cycles, radio is still a bit noisy when rotating so will treat it and the slide-switches with DeOxit Gold when I pull chassis. Really like having the meter for more precise tuning !

Pulled back cover this afternoon and chassis looks clean although there was a lot of dirt and dust collected where it came in through openings. It smells "musty" like it had been stored in a damp basement. Temporarily removed the tuner jack "pigtail" and mounted a sub-mini jack with proper size washers and wired to use my regulated 12V "brick" which I made for Royal 2000 & 3000 since I don't yet have the proper AC cord.

Because of very cold weather, am not going to mess with compressor in unheated garage to blow out---so will be awhile until major disassembly & refurb. Have done a bit more hand cleaning and found that there are several more small areas of light corrosion and a few more small chrome "blisters" and scratches. There is a spider web behind the dial glass... This appears to have been a well-used radio, but still is in pretty good shape overall---and just amazed on how well everything works after a little "exercise" ! Am probably going to put LED's in tuning drum since they turned out to work so well in the 3000...

The original owner's name & address in WV is on battery cover label and thought it neat that his 1st & last names are same as my 1st & middle names...

Also noticed info about trademark on battery cover interior label saying it was patented in Canada in 1961 ! From a couple date codes I spotted, looks like it was built around 1975...

John



John


Last edited by xrhonda91 on Jan Mon 28, 2019 1:55 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Sat 26, 2019 2:13 pm 
Member

Joined: Aug Thu 23, 2018 1:11 pm
Posts: 28
To Dave: thanks for the background on Zenith's reasoning for rolling off the treble response, ".... pearls before swine"!.

As far as what value to replace the 0.0033uf with, I simply removed the capacitor. With the 0.0033 uf in place, the audio response starts to roll off at about 5 kHz and my original intent was to open the bandwidth up to about 16 kHz, which would imply a value of about 900 pf. I found that once the capacitor at the driver base was out of the picture, other poles in the frequency response became dominant and the response rolled off at about 8kHz. I deemed that a sufficient improvement and left the 0.0033 uf out.

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O on the way---radio bug bit again...
PostPosted: Jan Sat 26, 2019 5:38 pm 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Thanks much, John !

Will play with that cap once chassis removed---may try a .001 uF just to see how it sounds...

John


Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O project---radio bug bit again...
PostPosted: Jan Mon 28, 2019 3:26 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 5729
Location: Indianapolis, IN
Progress report...

Disassembled and took pics along the way for reference. Chassis did come out easier than the 1000-D & 3000 and having the ferrite rod attached will make it easier to test outside of cabinet. All the chrome (including band-switch knob) has damage of some type from very fine pitting to scuffing. Most did shine up fairly well after vigorous cleaning and polishing... The tuning dial window also had some fine scratching and looks much better after Novus-2 treatment. A lot of dirt in cabinet recesses and crevices when apart and appears that radio was used outdoors a lot which makes sense since original owner was into hunting and camping. Also noticed that the "musty" odor has a bit of "campfire scent" to it... When speaker pulled, noticed that the foam in center had come loose and was laying against cone---not quite to the "crumb" stage yet...

Mentioned the tuning pointer not being straight in earlier post and found that the carriage guide spring ends were glued "crooked" from factory ! Carefully removed glue, bent the ends of spring as they should have been and rotated spring in pointer to give proper pointer distance from dial drum. Initially, tuned to WLW 700 on AM BCB and centered pointer on mark and bent one of the spring ends around dial-cord, then checked other AM stations and WWV on two of the SW bands and it was dead on ! Applied Loctite Go-2 Gel glue to both ends of carriage guide spring where they contacted dial-cord to secure---pointer now straight and accurate !

Looked into intermittent RF Gain control switch situation and it appears that the internal switch contacts are at fault---too much work now to remove and service, so will put off until later. It does work when shaft wiggled a bit, so control is usable...

Tried disabling the .003 uF disk cap on base of pre-driver transistor per John's suggestion to increase high-freq response and didn't notice any change in tone quality at low volume---but when turned up slightly, it broke into wild oscillation ! So soldered cap back into circuit...

Since this radio will not be a valuable "showpiece" when complete, decided to install LED lighting for tuning drum. Bought some "warm-white" LEDs for the Royal 3000 awhile back which worked great, so the parts were ready to go... Normally don't destroy original sub-assemblies when making such modifications, but since these radios are so common, decided to go ahead and remove the lamp sockets and use the mount pieces for the LEDs. Crushed and pulled off the threaded sockets and insulators. Straightened ends of brass rivets carefully with needle-nose pliers. Drilled out two power transistor insulating step-washers to fit over rivets and peened them into place. Soldered rivets on outside PCB strip for better electrical connection. Initially tried two LED's as I did in 3000, but noticed the ends of drum weren't very well illuminated, so added two more bent at slight angle which corrected issue---entire length now evenly lit... Used a 470 Ohm resistor in series. Wired tuning drum LED lighting directly to power switch leaving the chart lamp connected to momentary-contact slide switch as original...

Still have a LOT of tedious cleaning left to do before final pics and reassembly since the Tinnerman nuts on cabinet top pieces just spin and won't un-thread. The band-switch is working fine now (thankfully) after being used awhile, so am putting off the DeOxit treatment until needed...

Pics related to text below...

John


Attachments:
1ARF RD7000Y SPKR FOAM CONDITION.jpg
1ARF RD7000Y SPKR FOAM CONDITION.jpg [ 233.68 KiB | Viewed 517 times ]
2ARF RD7000Y DIAL POINTER CARRIAGE STRAIGHTENED.jpg
2ARF RD7000Y DIAL POINTER CARRIAGE STRAIGHTENED.jpg [ 201.9 KiB | Viewed 517 times ]
3ARF RD7000Y LED DIAL-LITE MOD 1ST TRY.jpg
3ARF RD7000Y LED DIAL-LITE MOD 1ST TRY.jpg [ 55.92 KiB | Viewed 517 times ]
4ARF RD7000Y LED DIAL-LITE MOD FINAL.jpg
4ARF RD7000Y LED DIAL-LITE MOD FINAL.jpg [ 66.61 KiB | Viewed 517 times ]
5ARF RD7000Y LED DIAL-LITE MOD INSTALLED.jpg
5ARF RD7000Y LED DIAL-LITE MOD INSTALLED.jpg [ 96.91 KiB | Viewed 517 times ]
Top
 Profile  
 
 Post subject: Re: Zenith RD7000Y T/O project---radio bug bit again...
PostPosted: Jan Tue 29, 2019 6:02 pm 
Member

Joined: Aug Thu 23, 2018 1:11 pm
Posts: 28
John -- Sorry about the bad results you got when you deleted the pre-driver cap. My 7000 is the first design (no suffix, fixed WX band tuning, plug-in loopstick like the 3000). The audio amplifier design is also slightly different than subsequent configurations, but the differences should show up only on the WX band where in the later configurations the gain of the pre-driver stage is made higher than on the other bands. Since I assume you were NOT listening to a WX report when you observed the oscillation, I am puzzled by our different results.

John


Top
 Profile  
 
Post New Topic Post Reply  [ 37 posts ]  Moderator: Dave Doughty Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests



Search for:
Jump to:  


























Privacy Policy :: Powered by phpBB