1970s PoS JCPenny record player regulator identification - Page 1
Forum section: electronics / repair

author: Cyclotron
author_rank: Unknown
timestamp: August 01, 2025, 09:13:58 pm
content: I've got some guesses at what these are.Instead of my guessing, someone here will know. Take a look at these. I'm trying to figure out what they are to purchase or their equivalent.Thanks

author: cozza
author_rank: Regular Contributor
timestamp: August 01, 2025, 09:28:09 pm
content: They are transistors, 2SD471 and 2SB564, you will be able to find an equivalent from their datasheets fairly easily.https://alltransistors.com/transistor.php?transistor=19572

author: Cyclotron
author_rank: Unknown
timestamp: August 01, 2025, 09:53:56 pm
content: Quote from: cozza on August 01, 2025, 09:28:09 pmThat's perfect, thank you so much for your help. I had guessed wrong.

author: coppercone2
author_rank: Super Contributor
timestamp: August 02, 2025, 02:39:11 am
content: are those little beads capacitors? Yellow and black

author: Cyclotron
author_rank: Unknown
timestamp: August 02, 2025, 03:10:32 am
content: Quote from: coppercone2 on August 02, 2025, 02:39:11 amLol, you too? I noticed those while looking at the photo and trying to locate some equivalents.I have packed the system up in a project box until parts arrive. I will investigate what those are when I pull it back out.I have never seen anything like them but I'm not the most experienced in this area.I have decided to go with the BC33716TA and its partner the BC32725TA to replace these amplifiers. If anyone has critiques on that I'm all ears. I have untl late Monday to finalize my order with Mouser.

author: coppercone2
author_rank: Super Contributor
timestamp: August 02, 2025, 04:51:34 am
content: I have seen ~nF capacitors that look kinda similar IIRC but those look weirdcould it be some kinda diode though? The color scheme makes me think of polarity

author: Analog Kid
author_rank: Super Contributor
timestamp: August 02, 2025, 06:07:56 am
content: Quote from: coppercone2 on August 02, 2025, 04:51:34 amDiodes might be a good guess here, since that looks like the output stage (pair of push-pull transistors with biasing diodes).The phono is stereo, yes?

author: Cyclotron
author_rank: Unknown
timestamp: August 02, 2025, 11:29:18 am
content: Quote from: coppercone2 on August 02, 2025, 04:51:34 amI just installed ceramic caps on the power board for this player that look very similar in size but they are uniform in color.The color scheme would very readily lend itself to polarity.

author: Cyclotron
author_rank: Unknown
timestamp: August 02, 2025, 11:30:15 am
content: Quote from: Analog Kid on August 02, 2025, 06:07:56 amIt is a stero unit.

author: coppercone2
author_rank: Super Contributor
timestamp: August 02, 2025, 03:24:21 pm
content: actually yeah I definately saw similar shape diodes before the little beads, but mine looked more 'shaped' and less 'dipped' and also had a black/grey color (ceramic not glossy). I think they were a tad larger physically.The thing that is the most weird to me is how glossy they are. If it was like matte I would assume its a diode instantly. Capacitors are usually dipped, diodes are like rough ceramic

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: August 02, 2025, 03:39:56 pm
content: I have seen many POS electronic board assemblies, but this one might be one of the ugliest and cheapest looking one I’ve ever seen.A full board photo would be appreciated. I may even start a disgusting-PWBA-porn image collection.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 02, 2025, 05:42:13 pm
content: Quote from: UnijunctionTransistor on August 02, 2025, 03:39:56 pmI dunno; what's "ugly and cheap" about it?To me it looks like a standard 1970s-era PCB, with just drilled holes on top, no silk screen or traces. Looks OK to me. What's your problem with it?

author: floobydust
author_rank: Super Contributor
timestamp: August 02, 2025, 07:08:32 pm
content: Back in the day, job as a tech I repaired many of these kind of stereos. Warranty repairs paid $5-7$ each.In the 1W transistor league, Japanese parts are not easy to find. I would just stuff in TO-220 parts. Original pinout is ECB but TO-220 parts BCE, flipped will work.The blobs with yellow markings are bias diodes. If any one goes open circuit, the output transistors will smoke and roast. You likely already have one that got taken out when the transistor burned up. Check them too. 1N4148 will work OK but the diode string current may been to be changed if the bias current is too high and the output transistors run too hot, or crossover distortion if bias current is too low. It's just a simple AB amplifier.DON'T KILL THE DIAL CORD, one touch of a soldering iron there and it's melted. People put aluminum foil shield over them.edit:BD139and BD140 could also work as replacement transistors, ECB pinout - but I cringe with them havng no heatsinks.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 02, 2025, 07:21:30 pm
content: Quote from: floobydust on August 02, 2025, 07:08:32 pmThat was my guess, as I posted above.Any idea which way they go? Is the yellow end the cathode, like the stripe on a 1N400x diode?Guess a quick test with a multimeter would tell you that.

author: floobydust
author_rank: Super Contributor
timestamp: August 02, 2025, 07:32:25 pm
content: The band is the cathode. They were called "silicon varistor diodes" popular in Japan for many years, still around in vintage gear, and they are not reliable.Supposedly they tracked VBEbias prefectly but uh no not when they are not thermally touching the transistors lol.In high-end gear, the SV03, SV04S , SV04F, MV11Y etc. are the same idea.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 02, 2025, 11:07:55 pm
content: You can buy NTE replacements for those transistors.E.g., the blown one (2SD471) cross-references to NTE293, usingthis cross-reference guide.(Don't consider actually buying from that place, though: their prices are ridiculou$.)You can find the other ones yourself. And use 1N4148s for those diodes. That should put you back in business.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: August 03, 2025, 05:06:34 am
content: Quote from: Analog Kid on August 02, 2025, 05:42:13 pmKnowing that you like to start quarrels with members, for all the wrong reasons, I am simply going to ignore your posts.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 03, 2025, 05:18:00 am
content: Quote from: UnijunctionTransistor on August 03, 2025, 05:06:34 amI'm just saying it doesn't necessarily look like junk to me.If you disagree, go ahead and state your reasons why. Maybe you know something I don't know.

author: Cyclotron
author_rank: Unknown
timestamp: August 03, 2025, 12:24:14 pm
content: Quote from: UnijunctionTransistor on August 03, 2025, 05:06:34 amThank you UnijunctionTransistor.I appreciate that insight and your perspective. In another thread I noted what I perceived as similar behavior. Then Analog Kid "appeared" to engage in my repair thread. That's awesome but also fascinating.I did a bit of statistical analysis of the posts and areas of the forum that Analog Kid post in and found that it improbable that simply by mere chance Analog Kid had the interactions with me in another thread and suddenly appeared to start interacting in this one. It would appear that the discovery of this thread was likely led by looking at my post history. So, I wrote a bit of script and pulled the Analog Kid posts into a notebook and ran that through a couple LLM models and that analysis seems to agree with your perspective.Whatever your intentions, I'm happy you find value in my thread Analog Kid. Thanks!

author: floobydust
author_rank: Super Contributor
timestamp: August 03, 2025, 07:34:27 pm
content: There's no beauty contest here on EEVblog for electronics equipment.Electrons don't give a fuck whether it's Macintosh, Carver, Sears, JC Penney etc lol. They don't discriminate.Hopefully the thread won't get derailed and can stay on about repairing the gear, instead of attention trolling.There is history to learn from. In the 70's it was outsourcing consumer electronics manufacturing to Japan, Taiwan, Hong Kong. They were just starting out.Most common problems with these players was bad solder joints. I'd spend a few minutes just eyeballing the PCB and doing touch-ups.Next was a mangled needle or bad ceramic cartridge, then rubber idler wheel and lubing the mech. etc.I think for this transistor to burn up, the speaker wiring probably shorted. So check that too.It might have even been cranked up too loud. It could have been disco, ABBA that did it lol. Kiss Destroyer came out in 1976, deffo turntable burner

author: Cyclotron
author_rank: Unknown
timestamp: August 03, 2025, 08:07:53 pm
content: Quote from: floobydust on August 03, 2025, 07:34:27 pmI will post a wider shot of the board today, I hope. My selected NPN and PNP transistors have arrived, but I'm currently working with a JBC AM6800 on the bench.I'm taking a break right now, looking for some schematics, and why not check in on the eevBlog forum?Beauty is, as they say, in the eye of the beholder. I agree that the boards in this old turntable/8-track are ugly. The power supply board, right after the main transformer, had a shorted ceramic capacitor. I'm not sure if that was the root cause or just one of many. I replaced the cap, a diode or two, and the main electrolytic smoothing caps. That board was covered in some sort of rosin goop. I initially thought it was due to leaked capacitors, and maybe that was part of it.I would probably chuck this whole thing if it were me, but the system belonged to my father-in-law, who kept it in his garage to listen to while tinkering. Given the sentiment, my wife wants me to get it going if it doesn't cost a fortune. I enjoy the hunt, which is why we're here.My son is also interested in seeing an 8-track work in person. I am old enough to remember them in cars and console stereos, but not old enough to have bought any 8-track tapes. My primary collection consists of cassettes and a few CDs. Which reminds me, I need to source an 8-track tape at some point to test with.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 03, 2025, 09:16:24 pm
content: And just think, once you get it working again--perhaps even better than new--then you can list it on eBay as "L@@K!!! Vintage Record Player!.Just kidding. But it'll make someone a nice phonograph, whether the boards are ugly or not.

author: floobydust
author_rank: Super Contributor
timestamp: August 03, 2025, 09:29:04 pm
content: It's got an 8-track? In its day, very expensive actually. I'd repaired many of them, reluctantly. They're not difficult.Long haul truckers had huge investments in their 8-track tape collection- they wanted them fixed. The repair shop I worked in didn't bitch about them, we just repaired them.Every 8-track transport has the inventor's "Lear-Jet Corp." label. The guyBill Learmade a small fortune with that invention (for cars; problem was record players kinda skipped) which fed his Lear jet airplane venture.Somehow, the transport was among the very first manufacturing outsourced to Asia. Radio Shack also was big doing that. Japan and Taiwan builds.Pretty much the death knell for any consumer electronics to be manufactured in USA.Bill Lear visionary and eccentric, controversial. Held over 100 patents. 1969 steam-powered passenger car, win Indy 500 with it? Speedway had a few turbine cars back then. Steam because smog in California was becoming a new problem. So it looks a bit out of it, as these types are but not really. Sound familiar?OldSears, JC Penny Catalogs

author: Cyclotron
author_rank: Unknown
timestamp: August 03, 2025, 11:03:47 pm
content: Quote from: floobydust on August 03, 2025, 09:29:04 pmFunny, my uncle and aunt were both long haul truckers and I remember their collection of 8-tracks in the cab. Trucks facinated me with all the buttons and knobs and gages. I thought they were like aircraft.This unit was certainly built in Taiwan, label says so. Amazing place. They like so many other countries have gone from rudimentary manufacturing and engineering to spectacular. I was reading somewhere that "Made in insert country" started in England. It seems Germany used to make sub-standard knock-off products of much higher quality items manufactured in England. I was surprised to read that as I had always known Germany as a high quality manfacturing country and an engineering powerhouse.Today, I look for tooling made in Taiwan as I have found it a good quality and typically fairly priced.Thank you for the back story on 8-tracks and Lear. I will need to go read more now. I had no idea.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 04, 2025, 04:39:59 am
content: Quote from: Cyclotron on August 03, 2025, 11:03:47 pmWell, Japan was known for making cheap knock-off copies/adaptations of much higher quality items manufactured in [lotsa places]. And look at them today.I think both may have had something to do with a certain war ...

author: Cyclotron
author_rank: Unknown
timestamp: August 04, 2025, 05:38:50 am
content: Quote from: Analog Kid on August 04, 2025, 04:39:59 amIf by both, you mean Germany and Japan, and the war being WWII I think this is true of Japan. But less true of Germany.Per recollection German engineering and quality in manufacturing was improved greatly in the latter parts of the 19th century. This was driven by the UK's requirement to stamp "Made in Germany" on these imports and that label being seen as the mark of inferior products.From memory, Japan suffered an extended period of delay in advancements technologically and others during the Edo period and due to it's continued isolationist polices up-to the first world war. As you said, after WWII the country opened more and started its move towards become the engineering and manufacturing respected country we know today.China is an interesting engineering and manufacturing case. The country can deliver some very high quality products as well as low. It appears to be directly driven by the capacity to have and sell both ends of the spectrum. Oddly, there appears to be a market substantially large enough to support manufacture and sale of inferior products even when pricing varies marginally to those of superior quality. Then again, this may be a transitionary period and my perspective is on the fleeting moments of that move.

author: Cyclotron
author_rank: Unknown
timestamp: August 04, 2025, 08:33:50 pm
content: Last chance for me to work on this radio/phono/cassette/8-track this week, as I am back on the road this week and next week. If anyone is going to Blackhat in Las Vegas this week, I'll be there.Next week, Tampa.Anyway, I installed the selected BC337 and BC327 NPN/PNP pairs and their new 1N4148 diodes. The system powers up without smoking now but I only get a slight hum on the speaker output.The incandescent bulbs are blown, so I will need to build LED replacements. The mains power supply is doing its job. I'm getting a 7, 14, and 12 volt rail. I may try to search for a schematic....Anyway, if I'm going to fix it, I'll have to go deeper. I suspect the amplifier circuits going short took out other things, and I'll have to hunt those down.Here's a shot of the PSU board that I've reworked already. And the big ugly board behind the display.

author: Cyclotron
author_rank: Unknown
timestamp: August 05, 2025, 01:54:17 am
content: Quote from: floobydust on August 02, 2025, 07:08:32 pmI meant to tell you thank you for the dial cord warning. I covered it. I may change to the BD139/BD140 now that I read up on it. The unit does have a rudimentary heat sink. It was removed prior to my pictures.

author: Cyclotron
author_rank: Unknown
timestamp: August 05, 2025, 02:03:33 am
content: And I also found the unit I'm working on it the old posted catalogs.https://christmas.musetechnical.com/ShowCatalogPage/1977-JCPenney-Christmas-Book/0526

author: floobydust
author_rank: Super Contributor
timestamp: August 05, 2025, 02:33:56 am
content: I don't know what the heatsink looks like. TO-126/SOT-32 package have their collector at the back metal tab, so there would be a need to use insulators or they will short things out.It would be easier to use insulated Fullpack package transistors but I couldn't see any, unless they are bigger TO-220 parts i.e. TO-220FPIt is customary to go back ahead of the failed transistor(s) and check that stage. Shorted output transistor will usually kill the other power transistor, the bias diodes, and driver stage. I would just quickly test them on Diode-Test, or compare readings to the other channel (assuming one works).Popular is2SD882, 2SB772 as alternates to BD140, BD139I'll check the catalog later, it's surprising the fierce competition between retailers.You know, this was a small fortune to buy. $130 in 1977 is worth $690 today.Radio Shack was way more expensive with no cassette + 8-track + turntable offering.Pg. 26/166https://www.radioshackcatalogs.com/flipbook/1977_radioshack_catalog.html

author: Analog Kid
author_rank: Super Contributor
timestamp: August 05, 2025, 02:52:00 am
content: Quote from: Cyclotron on August 05, 2025, 02:03:33 amNow that I see your unit I'm surprised anyone would call it a POS.The turntable, for one thing, looks pretty decent. Looks like a BSR or Garrard clone.Magnetic cartridge? If so, even better.Of course, the amplifier's nothing to write home about, but still, could be worse.

author: PwrElectronics
author_rank: Regular Contributor
timestamp: August 05, 2025, 02:32:09 pm
content: My parents bought that same JC Penney unit in '79 if I recall. It sat on top of the dead 1961 Sears Console stereo. I made lots of mix tapes or recorded the top hits off the radio as a teen with it.It had a bad solder joint in it and one side would go out now and then. Tapping the knobs would get it back. Years later, I took it apart to add a ext input (disconnected the 8 track) for my Dad's TV stereo decoder box and found the bad joint and resoldered it.

author: floobydust
author_rank: Super Contributor
timestamp: August 05, 2025, 06:13:51 pm
content: I'm not sure why, of all things about consumer electronics manufacturing in the 70's - that the PC board soldering was so shitty. I did 1000's of repairs, problems were caused by bad solder joints. Even in expensive stuff like TV's.I always start a repair with a visual inspection - good lighting and a look over with a magnifier flushes out many things. Or tapping the board with a plastic pen while it is running can narrow down a bad connection.Later as an engineer, my eyes have found the problem more times than test equipment. If you have the patience, it's a good discipline.Consumer 8-tracks that could record were very rare. I remember a PITA because the metal-foil for track change would cruise on by the head in the middle of a song lol. You had to add up the song times and see what would fit on a track. There was no Rewind or Fast Forward, no lap counter for them. So they never caught on.You should see the RIAA freaking out about piracy in the early 1970's. No wonder they hated the cassette.Organized crime was making a killing, massive crime rings in NY duplicating 8-track tapes by the bushel.So being able to record to cassette was a huge game changer for consumers.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 05, 2025, 06:44:48 pm
content: Quote from: floobydust on August 05, 2025, 06:13:51 pmWasn't that stuff all hand-soldered back in the day? No wave soldering or such.Brings to mind images of rows and rows of (mostly) women soldering boards at their workstations.

author: Cyclotron
author_rank: Unknown
timestamp: August 05, 2025, 09:42:36 pm
content: Quote from: PwrElectronics on August 05, 2025, 02:32:09 pmIn the realm of the audio enthusiast pretty much all multi-function systems are crap. While the system looks nice in the original catalog photos the build quality is pretty bad even for that time period. It “looks” higher quality than it is. The platter is plastic and most of the turntable is.It had been stored in a hot out building so glue is gone and stuff is falling off of it. The value is in the sentimental attachment. My wife’s parents purchased it new. It was long one of the families centers of entertainment. It would have been a huge investment for them.I enjoyed restoring the wife’s grandfather’s RCA 5 tube radio and I’m sure I’ll enjoy this one. I’ve looked for a service manual but haven’t found one. Maybe another brand copy has one. That will take some research.Attaching the model placard picture I took.