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 Post subject: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 5:31 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Hello All,

This Panasonic R-109 "popped up" while browsing with a $4.95 "Buy It Now" and just couldn't pass it by ! Only one small, "non-zoomable" picture in listing, but it appeared to be in good shape and came with owner's manual. Kinda bizarre that just over seven years ago I bought another (which was "buggy" and in worse cosmetic condition) for the same price ! Really like the fact that the tuned RF-amp stage is clearly "advertised" on front panel---and also has dial-light which illuminates entire area...

It arrived yesterday in a box not much bigger than itself wrapped in that "anti-skid" kitchen shelf liner---at least the box was sturdy, heavy cardboard ! It was in nice condition other than a small "melt-mark" over the "N" in "TUNED" which I very carefully shaved off with tip of a sharp utility-knife blade, dry then wet-sanded with 2000-grit, and polished with Novus-2. Looks much better, but still has a narrow groove at contact point of the "hot item"...

Inside very clean and original. Had forgotten how well these little sets were made ! Learned from 1st set not to even attempt removal of entire chassis due to difficulty of getting tuning pointer out of front panel slot without damage to its fluorescent paint ! Applied power with clip-leads to battery holder contacts and radio completely dead. Suspect the external power jack as it appears somewhat corroded. Will pull only the PCB to replace electrolytics---and there are a bunch !

Found this interesting article which is in Japanese: https://plaza.rakuten.co.jp/shigechan20 ... =1&ctgy=35 Is there anyone here who could translate for me ???

Cropped Ebay pic below---stay tuned !

John


Attachments:
ARF Panasonic R-109 ebay 4-25-19.jpg
ARF Panasonic R-109 ebay 4-25-19.jpg [ 72.76 KiB | Viewed 599 times ]
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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 6:46 pm 
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Joined: Sep Fri 07, 2007 2:27 am
Posts: 6082
Location: Grand Chute, Wisconsin
I just opened it in Google Chrome and clicked the "translate" button that popped up. Does your browser have that feature?

.


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 6:54 pm 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 9159
Location: Mountains of Mourne. Ireland.
Translate web-page...
http://itools.com/tool/google-translate ... translator

Greg.


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 9:30 pm 
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Joined: Jun Sun 22, 2008 2:03 am
Posts: 1409
Location: Burke, VA 22015
Hi John,

What a bargain you got! Looking for your report with more pictures of this radio.

The Japanese page as translated by Google:
https://translate.google.com/translate?hl=en&tab=wT&sl=ja&tl=en&u=https%3A%2F%2Fplaza.rakuten.co.jp%2Fshigechan2008%2Fdiary%2F%3FPageId%3D1%26ctgy%3D35

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Binh


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 9:38 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Thanks Guys !

I'm using Firefox, but just installed the "Google Translate" add-on---will give it a try !

Found initial power-on problem---the wire to negative contact spring in battery holder had come unsoldered, but was difficult to see and was apparently not discovered during previous repair attempt When inspecting the external DC power jack, found that someone had already bypassed the switch contacts---probably due to that open connection ! All this may explain why radio is in such nice shape for age...

But---after replacing the 10 electrolytics (which was not fun with chassis in cabinet and PCB removed as far as possible for access), still only got a "pop" in speaker when turned on ! Measured current and it was pulling over 250 mA !!! Am worried now that someone plugged in an incorrect "wall-wart" due to the battery contact issue and fried transistors---arggghhhhh !!!

More to come...

Thanks much , Binh---Was just getting ready to post and try new add-on and your response appeared !

John


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 9:55 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Hello Binh---just read the translation you sent, very interesting in that he had a couple of the same problems !

Back to the work table...

John


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 10:10 pm 
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Joined: Jun Sun 22, 2008 2:03 am
Posts: 1409
Location: Burke, VA 22015
Let's hope that the transistors are not fried. The power supply for the front end is filtered by one or more RC circuits. If you can locate this resistor, lift one of its ends up. Power up the radio. If high current is still observed, the fault is in the section before the power supply filter such as the push-pull output transistors, audio driver... Otherwise the fault is after the filter (the radio's front end). If the fault is in the audio output, check the NTC thermistor, diode, resistors that form a bias circuit for the bases of the output transistor pair. If the fault is in the front end, you have to disconnect the transistors one by one until the fault disappears.

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Binh


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Thu 25, 2019 10:14 pm 
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Joined: Jun Sun 22, 2008 2:03 am
Posts: 1409
Location: Burke, VA 22015
I read the Japanese restoration diary and it reminds me of all the good reports you've written. Not only he replaced all capacitors but also all resistors!

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Binh


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Fri 26, 2019 3:45 am 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Thanks Binh---noticed that pile of resistors !

Had already measured voltage on both sides of the 180 ohm and determined that it was being loaded on the input. One of the P-P output transistors had an E-C short and the 4.7 ohm emitter resistor was smoked ! The audio driver also had an E-C short. The pre-amp transistor voltages appeared okay and did get a slight "hiss" at collector with signal tracer. Got low level, distorted signal at 3rd IFT output now using RF probe. Much stronger/clearer signal at 2nd IFT output. Discouraged & out of patience, so stopped at this point. Apparent that someone DID plug an incorrect power source into external power jack---had same type thing happen with a Panasonic T-81... Even if front end transistors are working, they may have been degraded so performance won't be what it should. Am considering swapping PCB from 1st R-109 into this much better (cosmetically) set, performing complete alignment, and experimenting with silicon transistors for replacements on original... Since the tuning pointer on 1st is already stripped of paint, removing its chassis wouldn't be a problem...

The original instruction manual is like new and am concerned if scanning will damage the page creases---may just take good pics for anyone interested...

Few pics below...

John


Attachments:
ARF R109 BAT CONTACT WIRE OFF.jpg
ARF R109 BAT CONTACT WIRE OFF.jpg [ 132.32 KiB | Viewed 522 times ]
ARF R109 BAT HLDR & OLD CAPS.jpg
ARF R109 BAT HLDR & OLD CAPS.jpg [ 210.89 KiB | Viewed 522 times ]
ARF R109 VIEW BENEATH PCB.jpg
ARF R109 VIEW BENEATH PCB.jpg [ 222.18 KiB | Viewed 522 times ]
ARF R109 PCB NEW CAPS.jpg
ARF R109 PCB NEW CAPS.jpg [ 217.24 KiB | Viewed 522 times ]
ARF R109 OWNERS MANUAL.jpg
ARF R109 OWNERS MANUAL.jpg [ 213 KiB | Viewed 522 times ]
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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Fri 26, 2019 1:06 pm 
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Joined: Jun Sun 22, 2008 2:03 am
Posts: 1409
Location: Burke, VA 22015
It's a pain to work on the chassis without removing it from the case but you did a great job replacing the electrolytic capacitors and locating the short-circuit faults.

Since the bad and questionable transistors need to be pulled out, checked and replaced, it might be worthwhile to check the resistors surrounding these transistors too. These values of these carbon composition/film resistors have the tendency to increase with age. The resistors I'd always check are the power supply filter resistors. In this case they are 180 ohm and 120 ohm resistors (R34 and R11). Too high a value for these two resistors decreases the supply voltage available to the audio driver, pre-amp, IF and RF transistors.

It sounds like a good idea to swap the good chassis from your first set. If you're going to experiment with Si transistors on the bad chassis, I'd like to suggest two transistors: KSA733 (pnp) and KSC945 (npn). These inexpensive transistors made by On Semiconductor (formerly by Fairchild) have excellent hFE linearity and low noise. They are good for large-signal audio amplification as well as RF applications.

I'd like a copy of the manual if you're going to take picture of it...

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Binh


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Fri 26, 2019 3:21 pm 
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Joined: Aug Wed 26, 2009 1:50 am
Posts: 1517
Location: Mesquite NV 89027 (from Coventry, UK)
Nice little radio. It’s a pity about the transistors. Your idea of swapping the board from the working one would seem to be a good plan.


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Fri 26, 2019 4:02 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Thanks Guys,

Am getting ready to "attack" project this morning !

Binh---thanks for the transistor info ! Still have your e-mail, so will decide soon whether to scan or photograph...

Colin---sure hope transplant does well...

John


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Sat 27, 2019 4:58 am 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Busy afternoon !

Pulled the good 1st set's chassis, performed a careful IF alignment using AGC voltage as indicator (all three peaked well and were already nearly dead-on) since there will not be enough access when PCB wired to the 2nd set's installed chassis, printed out the SAMS PCB images, and marked the wiring locations and color prior to removing PCB--- also took pics from different angles for reference... Very carefully desoldered and removed wiring. Removed the mylar & electrolytic caps installed years earlier on good board and swapped in the newer electrolytics from defective PCB which I'd just installed yesterday. Placed the older, but still fine electrolytics in defective PCB which I plan to repair and installed correct low-value electrolytics which I now have stocked instead of the mylar caps subbed in years before...

Carefully wired good PCB into 2nd R-109's chassis, inspected closely, and applied power. All worked fine, thankfully. Dial tracking good. Adjusted ANT & RF trimmers---both screws already almost all the way out and sealed from factory (on both sets !) and any inward adjustment decreased sensitivity, so returned to original positions. Sensitivity very good & selectivity excellent. Plenty of clear audio from small speaker, but tone kinda flat. Stations are crowded at high end of dial and a bit touchy to tune with the small knob. Far from the best tuned-RF amp equipped radio in collection, but decent---if it wasn't for the dial panel styling with the reverse-painted "TUNED RF STAGE", wouldn't have much interest in this one...

Still need to detail clean the exterior and knobs which I hope to accomplish this weekend---as well as the final pics. And if weather bad, get the first set working and back together...

Few of today's pics below...
John


Attachments:
1ARF 109 1ST SET GOOD CHS OUT.jpg
1ARF 109 1ST SET GOOD CHS OUT.jpg [ 241.16 KiB | Viewed 452 times ]
2ARF 109 BAD & GOOD PCBS TOGTHR BOT.jpg
2ARF 109 BAD & GOOD PCBS TOGTHR BOT.jpg [ 220.96 KiB | Viewed 452 times ]
3ARF 109 BAD & GOOD PCBS TOGTHR TOP.jpg
3ARF 109 BAD & GOOD PCBS TOGTHR TOP.jpg [ 174.88 KiB | Viewed 452 times ]
4ARF 109 GOOD PCB EARLY RECAP.jpg
4ARF 109 GOOD PCB EARLY RECAP.jpg [ 237.85 KiB | Viewed 452 times ]
5ARF 109 GOOD PCB CMPLT.jpg
5ARF 109 GOOD PCB CMPLT.jpg [ 227.08 KiB | Viewed 452 times ]
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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Sat 27, 2019 12:39 pm 
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Joined: Jun Sun 22, 2008 2:03 am
Posts: 1409
Location: Burke, VA 22015
Hi John,

Glad to see the cosmetic transplant went well for the first set. Seven years after the first purchase, now you have a set that works well and equally looks good. Surprises me that the dial scale was made too short which makes the tuning crowded on the upper end - a little turn-off factor for me too.

Hope the weather is constantly good up there that you find no time to work on the bad chassis and decide to let it go... :wink:

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Binh


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Sat 27, 2019 10:41 pm 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Hello All,

Finished this radio today !

Detail cleaned the outside of cabinet & knobs (dirtier than it appeared), polished clear dial panel once more with Novus-2, touched-up scuffs in genuine leather with black Sharpie. Turned out much nicer than I'd thought !

Singed the end of battery pull ribbon with side of soldering iron as it was starting to fray.

Made an error in earlier post---the switch contact on external power connector is NOT used ! Thought a previous owner had moved battery wiring due to a broken connection, but the terminal had never been soldered ! Exactly the same on other set... Pretty surprised at this since the external power source would be in parallel with internal batteries if they were in place ! Am wondering if this radio design was rushed due to the poor design of tuning pointer installation, the tuning cap not being well-matched to antenna rod (ANT trimcap screws nearly all the way out on both radios), and this potential trouble-spot ! Chassis is well built, though, and uses a full-size volume ctl/pwr switch...

Radio is EXTRA sensitive to electrical noise from computer, camera, cordless phone, fluorescent lights...

Found the "luxury" cosmetic features such as genuine leather cabinet, orange velvet lined back cover, and gold printed instructions on sturdy inner cover pretty interesting...

Don't think I mentioned how small radio is in this thread---see 1st R-109 project for pic with a couple other radios for comparison: viewtopic.php?f=4&t=187449

Installed the "blown" PCB on earlier set's chassis and am preparing for troubleshooting---would be great to have another working set for comparison ! Decided to stay with germanium transistors at least for the front end since I have a scrap Panasonic pocket set in bench cabinet...

Anyone else have one ???

Did scan the like-new instruction manual and will send the raw files to anyone who PM's an e-mail address. Binh is 1st on the list !

Final pics below---gained more affection for this set once completed...

John


Attachments:
ARF R-109 CHASSIS INS CMPLT.jpg
ARF R-109 CHASSIS INS CMPLT.jpg [ 240.12 KiB | Viewed 415 times ]
ARF R-109 CHS CVR.jpg
ARF R-109 CHS CVR.jpg [ 232.16 KiB | Viewed 415 times ]
ARF R-109 INS CMPLT.jpg
ARF R-109 INS CMPLT.jpg [ 190.24 KiB | Viewed 415 times ]
ARF R-109 KNOBS CLN.jpg
ARF R-109 KNOBS CLN.jpg [ 253.16 KiB | Viewed 415 times ]
ARF R-109 CMPLT BK.jpg
ARF R-109 CMPLT BK.jpg [ 222.87 KiB | Viewed 415 times ]
ARF R-109 CMPLT FRT DIALITE.jpg
ARF R-109 CMPLT FRT DIALITE.jpg [ 164.83 KiB | Viewed 415 times ]
ARF R-109 CMPLT FRT.jpg
ARF R-109 CMPLT FRT.jpg [ 217.06 KiB | Viewed 415 times ]
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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Sun 28, 2019 1:24 am 
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Joined: Aug Sat 16, 2014 2:19 am
Posts: 1334
Location: Palos Verdes, CA
John - Another excellent restoration! I particularly like that the Panasonic R-109 has a light! - Mark


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Sun 28, 2019 1:24 am 
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Joined: Aug Sat 16, 2014 2:19 am
Posts: 1334
Location: Palos Verdes, CA
John - I'll have to keep a lookout for a Panasonic R-109 on eBay! - Mark


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 Post subject: Re: 2nd 1963 Panasonic R-109 project...
PostPosted: Apr Mon 29, 2019 4:50 am 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6010
Location: Indianapolis, IN
Thanks Mark !

Got the PCB repaired today and 1st set also now complete ! To try and avoid confusion, posted details in 1st set's thread: viewtopic.php?f=4&t=187449

John


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