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Pioneer SD-1100 Recap

xlbee

xlbee

PIONEERFREQ
Subscriber
I'm part way through recapping my SD-1100 and I just had one of those moments that made me do a double-take. It also made me realize that checking the polarity against the silkscreen for EVERY cap you replace is very important. The left picture below is of board AWM-034 (Complex Unit). The cap laying on the board is the same orientation as when I removed it. This picture has been flipped because the layout diagram on the right shows the back side or foil side of the board and I wanted them to visually align here. You can clearly see that the positive lead of C38 is silkscreened on the incorrect side.

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UPDATE: C28's polarity is also silkscreened incorrectly on the same board listed above.
UPDATE 2: In my service manual on the layout diagram for the "AF Osc Unit" board (AWX-033) there are 2 "C4" caps but one is actually C40.

This is a tricky unit to recap because of the errors, the wiring and the rather delicate traces. If you do one, BE CAREFUL! Also 1350 volts in the power supply!

Recap list is in post 16.
 

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Sheesh! The things you find while doing a recap. The picture below is of the Power Supply Unit (AWR-022). One end of C6 was NEVER soldered at the factory. This unit has been operating that way since it was manufactured in December of 1972.

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I guess at 1360 volts, solder doesn't matter so much ;)
 

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Like in one of my Spec-4s there was an unsoldered wire wrap pin on the fuse holder board. Only contacts were the corners of the pin touching the foil trace around the hole. Worked like that for 32 years.
 
Ed in Tx said:
Like in one of my Spec-4s there was an unsoldered wire wrap pin on the fuse holder board. Only contacts were the corners of the pin touching the foil trace around the hole. Worked like that for 32 years.
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Ed, that's crazy. When did you find it like that?
 
Not to sound like too much of an idiot, but why re-cap an SD-1100? It's not in the signal path. I absolutely love my SD-1100, but since it's working fine, and I see no leaky caps, there is no reason to recap, right? I'm sure I am missing something...please enlighten me!!!!
 
xlbee said:
Ed, that's crazy. When did you find it like that?
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About 2 months ago while going through both of them after repairing the R channel that blew up in the one amp. After finding bad solder connections on that amp board I decided it would be wise to check all boards in both amps.
 
Skylab said:
Not to sound like too much of an idiot, but why re-cap an SD-1100? It's not in the signal path. I absolutely love my SD-1100, but since it's working fine, and I see no leaky caps, there is no reason to recap, right? I'm sure I am missing something...please enlighten me!!!!
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Electrolytic caps are a comprised of a can, foil, an insulator, liquid and a rubber stopper in one end where the leads protrude. With heating and cooling, the seal can become weak and the caps can dry out. They are the one component in a solid state system that is prone to fail with age. Recapping a system that is working is like buying insurance. It may not be necessary but for the cost of a few caps and some time, it could save you a lot of time troubleshooting and replacing many components that might be damaged by a failed cap.

An ounce of protection is worth a pound of cure, a stitch in time saves nine etc etc.
 
Ran into the same situation recapping my Marantz Model 125 tuner.

C253 and C254 are silk screened improperly on the FM IF Amplifier board.

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I'd be happy to once I finish the recap and verify that everything is working. Should be ready to turn it on and do some testing tonight. (Fingers crossed!)
 
All done, adjusted and working perfectly.

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Ok, here's the recap list:

I do my parts lists in Excel with some fancy functions to convert Pioneer codes to meaningful descriptions and create BOM lists. Since we can't attach Excel spreadsheets, I saved it as a PDF.

Standard disclaimer: The attached parts list represents a snapshot in time. It's the right list for my unit, yours may be slightly different. Mouser part numbers change and they run out of stock so you may need to make some substitutions. The list should also be inspected by one of the AK gurus (you know who you are) to ensure it meets with their approval. The mods are more than welcome to publish it in the AK recap database if approved by one of the AK gurus.
 

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xlbee said:
The dual cap? Nope. I couldn't find anywhere to buy one (until last night).


If you can find a better supplier, let me know.
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Good to know a replacement is available. I figured it would be impossible to find, and that's the capacitor I figure most likely to fail.
 
Yeah, it will be really easy to go back in and replace that one. I'll get to it eventually...
 
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