SX-650 re-cap parts list - how does it look?

[Uncle Bambi]

Sounds like it is going pretty good. I hate it when I order the wrong parts.
I sometimes double up on caps of common values just to build up a stock, but still it seems I do not have the right cap anyway.


C62 is for the AM tuner looks like 25v cap would be fine measure actual
voltage.

C23 is for FM muting looks like working voltage is around 22v so that is why a 35v was specified. If you like measure the voltage across the cap to see what the actual working voltage is check with FM mute in and out.

As far as C101 and C105 these for the MIC circuit only come into play if a microphone is used.

Perfect - this is what I needed to know - THANKS!!

I have a Radio Shack close by, so I'll check there first before probing around. They usually have the common ones.

I'll leave 101 and 105 be, they are too much of a PITA to get to for a function I'll never use.

Now, the real question - do I chance changing c61 and c62? they are definitely on the "don't touch" list. If I do change them and screw up the alignment, can I replace the originals and get back to original function?

 

[Uncle Bambi]

Thanks for the play by play, I have a 650 that I plan on recapping (my first), and following you is giving me an idea of what I have in store. I can't wait to here your feedback on the final result.

This is kind of why I started this thread - I didn't see one like it for the 650. Glad I could be of some service!

Mine was a working unit when I got it, but had a broken power/speaker selector switch. I wanted to get practice re-capping, and this one is a little more simple than the 838 I cut my teeth on a while back. It's been very straightforward, with one or two caps that have been hard to reach. It has been more than worthwhile, as many of the caps that I've replaced have been bulged or had already begun to leak.

Be aware - there are one or two mistakes in my parts list so be sure to vet it before you order anything.

 

[Uncle Bambi]

I have a Radio Shack close by, so I'll check there first before probing around. They usually have the common ones.

I'll leave 101 and 105 be, they are too much of a PITA to get to for a function I'll never use.

Now, the real question - do I chance changing c61 and c62? they are definitely on the "don't touch" list. If I do change them and screw up the alignment, can I replace the originals and get back to original function?

(quoting myself... :nutz Ok - update:

Radio Shack had what I needed, so c23 has been replaced.

I was able to get to c105, so it's been changed. There's no hope for getting to c101.

So, that leaves c61 and c62 as the only original electrolytic caps left in the unit (aside from the aforementioned c101 which I cannot get to). What do you think - can I replace them or is the chance too great that I'll muck something up?

 

[goat67]

As I said C61 and C62 are for AM you seem to want to do them so go for it if AM stops working put the originals back in

 

[markthefixer]

C37 was risky.I hope c14 and c15 were left alone, BUT they're (all 3) only the stereo decoder which doesn't take a lot to get a reasonably close adjustment.

To my surprise, I couldn't really find any 'lytics around this 1138 circuit that were critical to alignment, they all turned out to be input or output conditioning / coupling or power filters...

:scratch2:

 

[Uncle Bambi]

As I said C61 and C62 are for AM you seem to want to do them so go for it if AM stops working put the originals back in

Only because the rest that I've pulled out were in such poor shape. I am trying to gauge the risk, and so am pestering you guys for your opinion because I don't know enough to make the call. That's why I asked about whether I can get back to the original state by re-installing the old ones if changing c61 and c62 throws the AM section out of alignment.

C37 was risky.I hope c14 and c15 were left alone, BUT they're (all 3) only the stereo decoder which doesn't take a lot to get a reasonably close adjustment.

To clarify - I did not replace c37. I did not touch c34-c37, or c61 and c62. Those are all original. I changed only the ones listed by Goat67 in reply #14, except those he bolded.

 

[Uncle Bambi]

Update, just to close this out.....

I replaced c61 and c62 with no apparent ill effects with regards to AM. Still getting good strong signals.

C62 was a 4.7uf 35v cap, and I replaced it with a 4.7uf 25v cap after taking Goat67's advice and measuring actual voltage (2.75v) before proceeding.

Looks like it was a worthwhile gamble, as both caps were slightly bulged at the bottom.

C101 is the only original electrolytic cap left in the system, and I cannot get to it so it stays.

This one is done.

 

[goat67]

Well you got another one finished good job enjoy.

 

[Uncle Bambi]

Well you got another one finished good job enjoy.

Thanks in no small part to you and Mark. :thmbsp:

I've got a Sansui AU-317II with a blown main fuse that someone gave me. It will probably be up next. I hope the guys in that forum are as sharp as you.

 

[markthefixer]

update to 3 year old parts list, part (d1616) becoming obsolete, plus choices were marginal (SOA q14, current drive q9) back then...
then again these parts were copies from other lists without reverse engineering, just a quick compatibility check...

gwr-101 q9 2sc945 512-KSC945CLTA power supply feedback regulator and drive
use: 512-KSC2383YTA to-92L ecb 160v 1a .9w 50mhz 160-320hfe

gwr-101 q14 2sc1647 512-KSD1616ALBU protection timing capacitor discharge
512-KSC2383YTA to-92L ecb 160v 1a .9w 50mhz 160-320hfe

 

[acetate]

Based on some issues during my restore (with input from many folks including Mark) it would be good to also consider replacing the relay. Mouser and digikey both carry them.

4pdt pcb mount 24v 653-MY4-02-DC24 MOUSER.COM stock level 82 @ $7.24

I will also add that some models have ICs in place of the phono amp (Equalizer Amp). Mine did and I spent quite a while insisting it must be hidden somewhere that I was forgetting to look. So check your unit before ordering parts.

Also caps, resistors, and transistors can be very different from the SM. Again check before ordering.

 

[bluehills5]

I'm just looking at this list and I've found the following parts with Obsolete status when importing into Mouser. Any suggestions for substitutes?

Mouser part Amt reqd Status
512-KSC2383YTA 2
512-KSA992FBU 3
512-KSC1845EBU 1 Obsolete -KSC1845FTA OK?
512-KSC2690AYS 1
647-QYS1H104JTP 5 Obsolete
647-UKL1E4R7KDDANA 2
647-UKL1H010KDDANA 3
647-UKL1H2R2MDDANA 6
647-UMT1C100MDD 2
647-UPW1A101MDD 3
647-UPW1A221MED 5
647-UPW1A331MPD 2
647-UPW1A470MDD6 4
647-UPW1H3R3MDD 1
647-UPW1J101MPD 7
647-UPW1J221MPD6 2
647-UPW1V221MPD 7
647-UPW1V470MED1TD 4
647-UPW1V4R7MDD 1
647-URZ1C471MPD 1
667-ECQ-V1H474JL3 4 Obsolete
667-ECQ-V1H474JLW 3 Obsolete

 

[goat67]

I'm just looking at this list and I've found the following parts with Obsolete status when importing into Mouser. Any suggestions for substitutes?

Used Polypropylene instead of Polyester Capacitors

Mouser part Amt reqd Status

512-KSC1845EBU 1 Obsolete -KSC1845FTA OK? YES

647-QYS1H104JTP 5 Obsolete 667-ECW-FA2J104J

667-ECQ-V1H474JL3 4 Obsolete 667-ECW-F2474JAQ
667-ECQ-V1H474JLW 3 Obsolete 667-ECW-F2474JAQ

 

[bluehills5]

Thanks.
Here is the new Mouser BOM list for anyone who wants to import with the above substitutions. Note this is for all the boards listed in this post excluding those the parts that were recommended not be replaced. It does not include the relay or the large filter caps.
Mouser Part Number,Quantity 1
512-KSC2383YTA,2
512-KSA992FBU,3
512-KSC1845FTA,1
512-KSC2690AYS,1
667-ECW-FA2J104J,5
647-UKL1E4R7KDDANA,2
647-UKL1H010KDDANA,3
647-UKL1H2R2MDDANA,6
647-UMT1C100MDD,2
647-UPW1A101MDD,3
647-UPW1A221MED,5
647-UPW1A331MPD,2
647-UPW1A470MDD6,4
647-UPW1H3R3MDD,1
647-UPW1J101MPD,7
647-UPW1J221MPD6,2
647-UPW1V221MPD,7
647-UPW1V470MED1TD,4
647-UPW1V4R7MDD,1
647-URZ1C471MPD,1
667-ECW-F2474JAQ,7

 

[emsrph]

Thanks guys for documenting and maintaining this list!

Just starting my first restoration. Purchased my SX-650 back in '76 or ('77?). Will be nice to get this back into usable shape. Needs deoxit on the pots and the typical re-capping.

So many components back ordered but I put my Mouser order in today,

 

[emsrph]

Doing a lot of reading trying to absorb all the good info here while waiting for parts and before diving in...

Is there a mistake in the BOM above for quantity of 512-KSA992FBU transistors? Should be 5 and not 3?

I realize that people in the know probably order extra dozens to create matched pairs for q1 and q2. But that wasn’t me, lol. Haven’t finished all the required reading still. I’m sure it’ll take me multiple Mouser orders to get it right anyway.

Thanks!

 

[emsrph]

Just realized I was confusing the 512-KSA992 replacement of q1 2sa725-g on the awk-065 board with q1 2SA798 on the awh-060 board...so BOM is correct.

But do people preemptively replace q1 2SA798 on the awh-060 board with two 512-KSA992? If so, I was reading that maybe in the sx-650 they don't need to be matched because the circuit would self-adjust?

 

[2ndserve]

Just a heads up, if you are going to recap the SX-650, be aware their are two different phono sections they used for it. The one already mentioned here and another that uses and IC, so pop the hood before ordering.

The IC version is the one found in the schematic body, the version mentioned in this thread is also on the schematic but in a little box at the bottom.

The IC version also had:

2 100uf 6v ecaps (replace with UPM, FC or similar)
2 220uf 25v ecaps (replace with UPM, FC or similar)
4 2.2uf 25v tant caps. (UKL or film)

As it has the IC chip, there are no discrete transistors to replace.

 

[emsrph]

Good point. thanks

Do you know the answer to:

do people preemptively replace q1 2SA798 on the awh-060 board with two 512-KSA992? If so, I was reading that maybe in the sx-650 they don't need to be matched because the circuit would self-adjust?

 

[2ndserve]

I do. HFE matching a pair of 992's for any 798 just makes sense to me. I can't say I've ever done that without doing other stuff at the same time, so maybe it makes no difference but it's certainly never hurt anything.