Sanui 3000A Volume Control and Output

[dly66]

Mouser and Digikey are the go to places. Order by 8 pm Central time Mouser normally gets it out to UPS or Fedex that night. Can be like a snipe hunt if you need an odd ball type for an old piece. Keep hunting good chance it can be found. Some things the lookup system for some reason does not make it easy to find them. I found these in Mouser's system:

https://www.mouser.com/ProductDetail/Nichicon/UEP1V102MHD?qs=/5szEjIr6f4%2b%2buzLWs2vVw==

Was considering tying together some 470 uF those go up to 50V and 63V. I used a small UEP cap in the Scott, they had a bipolar in the FM tuner section.

What was your source for those? I might want to check those out when I tackle mine.

 

[McGowdog]

Got it from the Bay, the guy almost way overcharged me for shipping, and seems to be out of the product. He also hasn't given me + feedback yet.

The product was about 5.27 per with about 17.50 shipping.

Well I ordered 4, and he charged me x4 shipping, so tried to charge me 69.00 to ship 4 tiny caps to one address. He knocked the shipping down for me, but not enough.

They seem to work fine in my rcvr, but if I had it to do over again, I wouldn't use that supplier out of GB.

I do have the other 3000a which has the seemingly factory cap mod mounted onto the shield with bracket, but don't like it. Those caps are so huge, you can barely get a fuse in and out and it's hard to access the trd.68 board. Obviously, you could just remove the shield and set it aside.

But can these factory mods still be found?



Oh, it removes nicely.

 

[kevzep]

I would'n use caps that old in anything, I am currently working on this CA303 1970? and all the electrolytic caps I have pulled from this are reading more than 50% over their rating, so they are failing and turning into resistors...bad bad bad...
You need to get some new caps in that thing sooner rather than later, dont even consider using those....

Some people may beg to differ, but I have seen too many caps failing and causing damage.....

 

[McGowdog]

Don't like them either. Maybe I can trim the bracket down or just use it as is and put my two remaining overpriced blue bipolars in there.

 

[kevzep]

Don't like them either. Maybe I can trim the bracket down or just use it as is and put my two remaining overpriced blue bipolars in there.

How old are those Sprague caps?

Go new, get two 470µf or better still two 680µf 50V and put them in series, job done!!

 

[dly66]

Those are Elna. The 3000/3000A ('67-69) pretty much same period as the CA-303 ('68-69) if a quick web check is accurate.

Those Nichicons available in 470 uF at 50V and 63V. No 680. Would probably tie 2-3 470-50 together figure out a friendly mounting arrangement, maybe sideways against the panel surface strapped in somehow. Mouser shows 140 currently in stock at $2.42 each

Every piece I have recapped it has made a huge difference. I use film caps for the small ones, 3.3 uF usually my transition point. Had to recap the Scott ('69-71?) just to get where I could diagnose it. It tuned and turned on the stereo light but everything out of it either amp at speakers or tape monitor was massively garbled. After recap I had at least one channel sounded good, totally lacked bass but sounded good.

 

[dly66]

In some of the old ones I have worked on the small value tantalum (little small oval plastic covered blobs - often blue or multi colored) and the solid aluminum caps can't be ignored. Measure their ESR values and they can be 15-16 ohms. They become resistors in their old age. There are a number of small solid aluminum caps in the 3000A.

 

[kevzep]

Open up a Tektronix 465 scope and you'll find out all about tantalum capacitors!!
They are riddled with them, the colour code type too, just to get your head spinning with calculations!!

 

[dly66]

I overhauled a Kenwood KR-7400. They used a lot of them in that design. Replaced them with Kemet R82 film caps.

 

[dly66]

I thought you might find this thread useful if you have not already found it. I saved it in my list for when I work on my 3000A which will be like the guy who started the thread one of my two winter projects acquired on the cheap so far. Some of these vintage units recapping, finding bad transistors and replacing likely troublemakers, relighting, and fixing cosmetic issues can take a good bit of time, especially if mainly done in the evenings after work.

mtflycaster in the third post from bottom gives suggestions for replacements and also gives voltages to measure across the new emitter resistors installed with the service bulletin mods so you don't have to do the current thing at the fuses. Measuring the voltages should be much simpler.

http://audiokarma.org/forums/index.php?threads/sansui-3000a-restoration.728452/