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 Post subject: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Thu 11, 2018 7:53 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
I found one of these locally in pretty rough shape with a weak but usable CRT. The chassis has some serious rust in spots especially around the three 6J6 tubes in the rf amp, converter and oscillator. It looks to me like the tube sockets should be replaced so I removed the tuner but I don't see how it's possible to replace the sockets. I have a glass bead blaster that works great on precision parts so I carefully blasted all the rust off the sockets. They look fine now except some of the tin plating is absent from a few of the socket pins. I have replaced all capacitors except for the ceramic and mica caps.

I brought the set up slowly on a variac and at about 90 volts saw some of the filaments light up. At 120 volts all the tubes light up except for the three 6J6's. The high voltage section seems to work as there is a strong arc from the 1B3 plate cap to a screw driver. There is a very dim raster on the CRT but only visible in a dimly lit room and only the lower 1/2 lights up.

All candohm resistors were replaced with aluminum housed wirewound as a few sections were open.

Seems like I'm almost there but am stumped as I don't know why this section is not working. All three 6J6's have good filaments as I tested them in a working set

Any Ideas are welcome! Thanks in advance!


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Thu 11, 2018 11:29 pm 
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Joined: May Sun 07, 2017 11:35 am
Posts: 281
Since the three 6J6s have no heaters, it seems more likely that you have an open circuit heater connection to the first one. No, or wrong, 6.3v connection to the tuner?

I don't know the 630TS but I assume it has an incremental tuner with ganged wafer switches like the early AWA tuners with which I'm familiar. It's a lot of work to replace a socket but it's possible. I'd see that as a last resort though. It might be easier to replace the bad contact insert in the socket with the socket in place. It is always better to disturb as little as possible.

I envy you guys, having access to such amazing old TVs. The oldest I have is a 1956 Ekco TX275. It's a 10" roundie and a portable - it can run from 12v DC, but you'd better have a big battery or leave the engine running! The CRT is interesting, it's a pre-war triode gun design from Mazda. We saw very few imported TVs in Australia back then because of import tariffs so this TV is rare. I believe it was installed in a caravan (trailer) and used to do coverage tests prior to official start of TV in Victoria.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Thu 11, 2018 11:45 pm 
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User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5256
Location: Woodinville, WA USA
Did you ever clean the contacts inside the tube sockets? This article talks about socket cleaning:

https://antiqueradio.org/FirstStepsInRestoration.htm

For nasty cases, you can get a little stainless cleaning brush as explained in the article:

Image

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Fri 12, 2018 12:01 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1648
Location: Lafayette, CO
Or replace that tuner assembly....leave me a message. Craig


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Fri 12, 2018 12:20 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 281
Given the rust, I'd grab a replacement tuner if it exists!

Way to go!

I didn't have that option with my rusty and siezed AWA tuner (similar to a US incremental RCA tuner of mid 50's vintage). It was a LOT of work to rebuild it and it still has a long-term intermittent fault that I suspect is due to one of the feedthru caps. That would be very painful to replace.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Fri 12, 2018 2:23 am 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
The tuner assembly is also broken. It no longer clicks and locks into place as the dial is turned. The ball bearing and retainer are absent because the retainer broke due to fatigue. A replacement tuner sounds like the way to go. Thanks everyone!

I had a great deal of difficulty working in this area of the chassis. It is very tight, and with the tuner removed I can double check my connections.

Thanks Craig! I'll message you.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Fri 12, 2018 2:30 am 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Message sent.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Sun 14, 2018 12:28 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
I made an error in wiring the heater connection and have corrected it. Now this section is working, but only briefly.

I got a raster but it is only a bright horizontal line about an inch high. I was wondering what would happen if I tried to change the channel, so I tried to turn the channel selector one click but I must have bridged two channels.Turns out this was not a good idea. Smoke! Pulled the plug and turned the chassis over to discover all the inductors that are daisy chained in the heater wiring are all charred. I think there are six of them. Everything else looks fine. Finding replacement parts seems unlikely. Hopefully I have not done more damage. Perhaps I could wind new inductors with the correct gauge of enameled wire.

Overall not a good day.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Sun 14, 2018 2:45 pm 
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Joined: May Sun 07, 2017 11:35 am
Posts: 281
Yes you can do that, it's actually as simple as it appears and the wire gauge and number of turns is not at all critical here.
Sounds more like you've got a broken piece of metal floating around in there somewhere and it shorted your heater circuit.

Can I recommend this trick if you can't find the culprit straight away? Wire an old-school car headlamp bulb (12v, about 50 watts) in series with the heater supply to the tuner. The cold resistance of the lamp is very low but increases greatly if a short happens, protecting your wiring until you find the short. This will keep the smoke inside!

Just a variation on the old dim bulb tester.

I had to rebuild the detent mech on my AWA tuner too. Set is a goer, it's now in a museum in Canberra.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Jan Mon 15, 2018 12:29 am 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Thanks irob2345!

I'll try your suggestion with the 12V headlamp bulb. Replacement tuner on it's way soon! Much rust removal to do in the meantime.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Tue 06, 2018 7:22 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Making slow progress. Got a replacement tuner from Craig at analog.tv. Thanks Craig! The shaft on it was too short so I decided to use it to fix the broken detente mechanism in my tuner which looks okay inside. What a job!!! I did finally manage to get everything apart and back together and have re installed the tuner.

Rebuilt the bleeder resistor compartment with chassis mount wirewound, and have replaced all electrolytics and film caps. No mica or ceramic caps have been touched. I now have a raster but no sound, except for a loud buzz when i turn up the volume control. I tried the set hooked up to my VCR. Vertical hold and horizontal controls work but picture will not sync. All controls seem to work and interact with one another. Checked my B+ which is a bit high at 325VDC. Checked voltage on V1 with picture control at minimum and got 135VDC. Chart says 125. With control at maximum I get 125 V, Chart says should be 55. Not sure how to proceed from here.

Thanks in advance for any suggestions!


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Fri 09, 2018 7:27 am 
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Joined: Jun Thu 25, 2015 3:21 am
Posts: 1239
I now have a raster but no sound, except for a loud buzz when i turn up the volume control.

if you are geting video on the crt first check all tubes in the audio section. while doing the short test gently tap each tube with a pencil eracer. dont forget the gas test. alternatively you could check the tubes by substitution with known good tubes.if all tubes are ok use signal tracer to check which stage in the audio is at fault then voltage measurements should point to which part of the circuit is at fault. then individual component checks will find the bad part. if you are getting no video on the crt then it would be the rf and if sections you check same as above.

I tried the set hooked up to my VCR. Vertical hold and horizontal controls work but picture will not sync.
this could possably be a problem caused by your vcr. try another signal source. the copy protection on vcr tapes can mess up the sync on old tvs. also it cant hurt to check all tubes in the vertical circuit and horizontal circuit and sync seperator circuit. after checking tubes check voltage measurements at the tube sockets. if voltages are within +- 20 percent things should be ok.

Checked my B+ which is a bit high at 325VDC. what is the b+ suposed to be on the chart.

remember all voltage and resistance charts are + - 20 percent unless otherwise specified. if b+ is within 20 percent of value stated in chart dont worry about it.

Checked voltage on V1 with picture control at minimum and got 135VDC. Chart says 125. With control at maximum I get 125 V, Chart says should be 55. Not sure how to proceed from here.
check all components in the picture control circuit.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Sat 10, 2018 1:56 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Thank you thomas13202! I will try your suggestions but I do not have any other tools other than a digital multimeter and a weller ESD51 soldering iron. My VCR works fine with another set, an RCA 8T241 which is from 1948 I think. If I turn this set on before I turn the vcr on it does not sync, but once the vcr is playing if I turn the set off briefly and then back on it syncs fine.

I think I have done just about all I can with this set with what I have to work with. I can test all the tubes in my working 8T241, then do some more voltage checks and replace any high value resistors that have drifted more than 20%. All voltage checks I have done so far are well within 20%.

There is a local TV repair shop near me. Perhaps I should let a professional take a look at it, but I don't want to spend too much money on this set, Does anyone have a rough idea what it might would cost to fix assuming there are no parts that need replacing?

Thanks everyone!


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Sat 10, 2018 8:05 pm 
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Joined: Mar Sun 01, 2009 10:27 pm
Posts: 4518
Location: Ann Arbor, MI
Is it both the horizontal and vertical that do not sync, or just one of those? The vertical section especially requires that all parts are close to the correct values. The sync separator needs the resistors to be close to the correct values.

Do try the tubes in another set or try tubes from a working set in this set. Before you give up, replace any mica caps in the sync separator and horizontal sections. We used to think that mica caps never went bad, but are now finding out that those with a lot of voltage across them are failing.

_________________
Tom


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Sun 11, 2018 2:02 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 281
Maybe the RF signal level is too high?
Try pulling the antenna plug very slightly out so it's nearly, but not quite, making contact.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Sun 11, 2018 4:47 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Thanks irob and Tom and others!

I've decided to try and fix and install the other tuner I got from Craig at analog.tv. Thanks Craig.When the inductors in the heater string went up in smoke I think it was from a blob of solder that fell into the tuner. I could not see anything in there but shook and banged the chassis on my workbench and a blob of solder fell out from somewhere. Perhaps it did some damage inside the tuner. I do not get the voltage swing on V1 on pins 1&2 when adjusting the picture control from min. to max. The chart says 130V to 55V whereas I get 135V and 125V.

I tested as many tubes as possible in my working 8T241 and many seemed weak with a noticeable degradation in the picture. My 5V4G went south this morning, so now no raster. Ordering new tubes.

Working on resizing and posting some pictures, so I'll be making some updates when I get the tubes and other tuner installed.

Thanks again!


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Sun 11, 2018 6:41 pm 
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Joined: Jun Thu 25, 2015 3:21 am
Posts: 1239
ok if you are planning on seriously working on tvs you will need more test equiptment
when I'm more awake I will try to give you a list of the basic ones. I have been up all night.

signal tracing the audio: I am not at all familiar with a dvm so I'm not sure if you can do this with one. if you have access to a vtvm it will work. the signal voltage is ac so a vtvm set to ac can be used to check where the signal is lost. I'm not sure if a dvm can be used to measure ac at the same terminal where dc is present. but you would measure for ac at the control grid of the tube and then the plate and work your way through the audio stage till you find where the signal stops. use an isolating condenser (old name for capacitor) in series with the positive lead makes measureing ac at the plate a bit safer.

all weak or dead tubes do indeed need to be replaced as well as gassy tubes.

you do really need a good condenser tester. even when installing new condensers you should run them by a condenser tester first. nothing worse than installing a new part then spending hours troubleshooting a problem just to find out the new part was bad. not one of the digital condenser testers as these don't put enough voltage on the condenser to properly test it. they are good for the low voltage condensers used in solid state equiptment though. Sprague made some excellent condenser testers and they are available on ebay every once in awhile.

tv shops today know nothing about vacuum tubes unless you find one where the tec was around during the vacuum tube era. even in the late 90s this was true. I went into a tv shop in early 2001 to purchase a tube and I found out the original owner had died and the young tec who took over for him told me he threw all that old stuff out. he also told me when he went to electronics school all they told him about vacuum tubes was that they were obsolete and you will never see any equiptment that uses them. of course if the tec is a antique electronics buff then he will know. if you decide you need help then check antique radio clubs in your area and they may know of someone who would be willing to help.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Mon 12, 2018 8:04 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
Thanks thomas13202! I found someone fairly close by who has quite a bit of test equipment for sale on craigslist: https://providence.craigslist.org/ele/d ... 95220.html I will be meeting with him on Wednesday of this week. Hopefully he will have what I need. I thought a good book might help, so I bought a book on ebay https://www.ebay.com/itm/Elements-Of-Te ... 2507762495

Going to take a break now, Hope you got some rest!


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Feb Wed 14, 2018 8:44 am 
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Joined: Jun Thu 25, 2015 3:21 am
Posts: 1239
the book you chose is a very good one. that brings me back to the days i was learning how to service electronics. markus was a very good author on the subject.

the vtvm you chose should work well for you. what is good also is it says it has the probes with it. one thing you should check with the seller is becides the ac dc probe does it have the rf and high voltage probe also and has it been reciently calibrated.

also helpful would be a book that shows pictures of what the crt looks like with different troubles and the most common cause for that problem. i used to have one of these but i forget the name of it.

with vintage test equiptment it may need some repair to get it functioning properly. there is a good book on this that i believe is being sold on antique radio clasified. again i cant remember the name.

one good thing to do is take lots of notes as to what you did while serviicing the equipttment to keep track of what you already did. i used a tape recorder to do this.


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 Post subject: Re: Crosley 9-408 [RCA 630TS clone]
PostPosted: Mar Thu 08, 2018 2:53 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 90
I went ahead and got the VTVM. It's a Micronta, made in Japan for Radio Shack. It works, but needs calibrating and or restoration in order to use it though. Here is what it looks like: https://www.radiomuseum.org/r/micron_va ... _vtvm.html
I took the back off the unit and everything inside looks new. There is a 20 uf. electrolytic cap that looks fine and measures 21 uf. Are there any parts in here I should replace because of age? I am guessing that this unit was made in the mid 1960's.

It came with all the probes as far as I can tell. There are two inputs on the lower left of the meter,one is common. a black wire with an alligator clip, and a red wire with a probe for measuring AC ohms. There is another probe for measuring DC ohms that has a screw on connector that connects to the lower right. This probe has a DC resistance of 1 meg. I found a free download for the book, "The V.T.V.M." by Rhys Samuel. So at least I can learn how to use it.

I will have to ship this to someone to have it calibrated and am wondering if anyone here might be able to recommend someone in the northeast who might be able to help me out.

Thanks!


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