Pioneer A-88X recap help

MadeMine

Active Member
I found an A-88X integrated amp to fix up. Everything works on the amp, it is missing wood side panels but is in descent shape. I measured some of the capacitors and were way out of spec. I want to do a recap on it. Does anyone have a list on a total recap.

Someone replaced the two center 10,000 mfd -71volts capacitors with smaller in diameter and height ones and glued them in, and the brackets that hold them in are missing. If any one knows a good place to get some replacement brackets would be great.

Any other tips would also be great help to fix up this amp.

Thanks
 
Worked on some.
I did not need to replace the big caps on them.
Pay attention to the power board which is upside down - no escape for heat, and some resistors run really hot there. When working there - careful not to destroy traces; they will be very brittle.
I did replace all power resistors on power board with higher power values. Positions are R1, 11, 14, 15, 17, 20, 21, 22. Vishay CPF, RS, CW can be used.
Zeners might be replaced, too.
Capacitors preferably UPW, UPA, UHE.
Check speaker relays. You can replace them with Omron G4W-2214P-US-HP or Panasonic JC2-aF-DC12V-F.
On voltage amp board you can replace regulator caps with hi temp new ones, might be 100V. Pay attention to cap diameter there - the spacing is very tight. Check UPA, UHE or FC - they come in narrow versions. Zeners, too.
Replace C3, 4 with high quality audio cap such as UKZ or RFS II. C9, 10 with ES.
C17, 18 with polystyrene such as PPFX or RTX.
R23, 24, 35, 36, 59, 60 high quality metal film resistors i.e. V-D RN, CMF PTF, PRP, old Holco etc.
Other film caps can be substituted with FKP2, polystyrene, Silver mica etc.
Replace relay RY1 on Tape Ind. board with Omron G5V-2-H1 12V.
Tone assy recap - as you wish. Sound path caps can be used UKZ or RFS II, C7-10 - FM, FC, UKW, UKL.
Original Op-Amps might be M5210 or M5220 depending on the year. They are adequate. As rails are 22V, there is not much to chose. NE5532, OP275 and LME 49860 are suitable subs.
Check power amp boards for overheated resistors, replace C43, 44 with UHE, UPW, UPA. C37, 38 with UET, UEP bi-polar.
Resistors R113-116 can be upgraded to non-inductive Mills MRA or Vishay NS.
Same recap principles could be applied at Equalizer (phono)board.
Replace VR1,2 with Bourns (such as 3339)
Thoroughly perform De-Oxit procedure on all switches and pots.
When disconnecting those numerous ribbon cables, use color markers, and take pictures.
Might re-seat power transistors with new heat transfer compound.
Re-flow solder joints with fresh one - please use lead containing eutectic. Do not use lead-free.
Treat wire wraps as advised on this board many times.
Very good amplifier with decent phono stage imho, thanks for restoring it and good luck.
 
Thanks hennessy, for all. I'd like to order all the replacement capacitors at once including the big ones. Do you have a complete list of an A-88X that you've rebuilt.
 
No I do not. I do have notes only. I carry a stock of components, therefore I do not need to order most of the time before any work.
 
Thanks hennessy, sounds cool does any one else out there have any knowledge of the A-88X capacitors.
 
do you mean a cut and paste ordering list?

like these??

might have to make one....
(or at least start, from the parts list in the manual, and folks will add in their parts numbers...)

The A-88x isn't one of our most commonly recapped units...

meaning you are treading new ground... AND get to be immortalized in marty's thread!!

BUT, everything's applicable to it.
 
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Thanks Markthefixer, This is what I have so far from the schematic. Need to cross reference to like Mouser.

A-88X CAPACITOR LIST

EQUALIZER ASSEMBLY (GWF-160)
C13, C14, (1000µF/25V-)
C23, C24, (22µF/50V-)
C113, C114, (330µF/50V-)
C105, C106, C107, C108, (2.2µF/50V-)
C101, C102, C103, C104, (220µF/50V-)

VOLTAGE AMPLIFIER ASSEMBLY (GWH-168)
C3, C4 (330µF/50V-)
C9, C10 (470µF/25V-)
C29, C30, C31, C32 (220µF/63V-)
C33, C34, C35, C36 (47µF/63V-)

L OUTPUT ASSEMBLY (GWH-169)
C43, (470µF/10V-)
C37, (2.2µF/100V-)

R OUTPUT ASSEMBLY (GWH-170)
C44, (470µF/10V-)
C38, (2.2µF/100V-)

TONE ASSEMBLY (GWG-186)
C1, C2 (2.2µF/50V-)
C3, C4, C7, C8, C9, C10, C17, C18 (10µF/50V-)
C13, C14 (1.5µF/50V-)

POWER SUPPLY ASSEMBLY (GWR-203)
C7, C8, C9, C10 (470µF/50V-)
C1, (100µF/100V-)
C2, (3.3µF/50V-)
C4, (33µF/16V-)
C5, C6, (10µF/50V-)
C3, C4, C5, C6, (10000µF/71V-)
C7, C8, C9, C10, (470µF/50V-)
 
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good for a first try, here's the preferred format:

a-88x gwf-160 c13 1000 25 ceya
a-88x gwf-160 c14 1000 25 ceya
a-88x gwf-160 c23 22 50 ach-056
a-88x gwf-160 c24 22 50 ach-056
a-88x gwf-160 c113 330 50 ceya
a-88x gwf-160 c114 330 50 ceya
a-88x gwf-160 c105 2.2 50 cexa
a-88x gwf-160 c106 2.2 50 cexa
a-88x gwf-160 c107 2.2 50 cexa
a-88x gwf-160 c108 2.2 50 cexa
a-88x gwf-160 c101 220 50 ceya
a-88x gwf-160 c102 220 50 ceya
a-88x gwf-160 c103 220 50 ceya
a-88x gwf-160 c104 220 50 ceya


a-88x gwh-168 c3 330 50 ceya
 
Thanks Markthefixer, Here is the preferred format for the A-88X capacitor list.

Could you check it out please. I really don't know the difference between the ceya and cexa etc. I took a wag, could you let me know the difference.

A-88X Capacitors:

a-88x gwf-160 c13 1000 25 ceya
a-88x gwf-160 c14 1000 25 ceya
a-88x gwf-160 c23 22 50 ach-056
a-88x gwf-160 c24 22 50 ach-056
a-88x gwf-160 c113 330 50 ceya
a-88x gwf-160 c114 330 50 ceya
a-88x gwf-160 c105 2.2 50 cexa
a-88x gwf-160 c106 2.2 50 cexa
a-88x gwf-160 c107 2.2 50 cexa
a-88x gwf-160 c108 2.2 50 cexa
a-88x gwf-160 c101 220 50 ceya
a-88x gwf-160 c102 220 50 ceya
a-88x gwf-160 c103 220 50 ceya
a-88x gwf-160 c104 220 50 ceya


a-88x gwh-168 c3 330 50 ceya
a-88x gwh-168 c4 330 50 ceya
a-88x gwh-168 c9 470 25 ceya
a-88x gwh-168 c10 470 25 ceya
a-88x gwh-168 c29 220 63 ceya
a-88x gwh-168 c30 220 63 ceya
a-88x gwh-168 c31 220 63 ceya
a-88x gwh-168 c32 220 63 ceya
a-88x gwh-168 c33 47 63 ceya
a-88x gwh-168 c34 47 63 ceya
a-88x gwh-168 c35 47 63 ceya
a-88x gwh-168 c36 47 63 ceya


a-88x gwh-169 c43 470 10 ceya
a-88x gwh-169 c37 2.2 100 cexa


a-88x gwh-170 c44 470 10 ceya
a-88x gwh-170 c38 2.2 100 cexa


a-88x gwg-186 c1 2.2 50 cexa
a-88x gwg-186 c2 2.2 50 cexa
a-88x gwg-186 c3 10 50 ceya
a-88x gwg-186 c4 10 50 ceya
a-88x gwg-186 c7 10 50 ceya
a-88x gwg-186 c8 10 50 ceya
a-88x gwg-186 c3 10 50 ceya
a-88x gwg-186 c9 10 50 ceya
a-88x gwg-186 c10 10 50 ceya
a-88x gwg-186 c17 10 50 ceya
a-88x gwg-186 c18 10 50 ceya
a-88x gwg-186 c13 1.5 50 cexa
a-88x gwg-186 c14 1.5 50 cexa


a-88x gwr-203 c7 470 50 ceya
a-88x gwr-203 c8 470 50 ceya
a-88x gwr-203 c9 470 50 ceya
a-88x gwr-203 c10 470 50 ceya
a-88x gwr-203 c1 100 100 ceya
a-88x gwr-203 c2 3.3 50 cexa
a-88x gwr-203 c4 33 16 ceya
a-88x gwr-203 c5 10 50 ceya
a-88x gwr-203 c6 10 50 ceya
a-88x gwr-203 c3 10000 71 ceya
a-88x gwr-203 c4 10000 71 ceya
a-88x gwr-203 c5 10000 71 ceya
a-88x gwr-203 c6 10000 71 ceya
a-88x gwr-203 c7 470 50 ceya
a-88x gwr-203 c8 470 50 ceya
a-88x gwr-203 c9 470 50 ceya
a-88x gwr-203 c10 470 50 ceya
 
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Hey thanks Markthefixer, good reading. Looking through the list so far, the ach-056 model is for a much larger capacitor. I'll change that when I find the right model to fit.
 
Bringing the manual up to 400%. It reads.

ach-456 instead of the ach-056

a-88x gwf-160 c23 22 50 ach-056
a-88x gwf-160 c24 22 50 ach-056

I'll go through all list in the manual.
 
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Bringing the manual up to 400%. It reads.

ach-456 instead of the ach-056

a-88x gwf-160 c23 22 50 ach-056
a-88x gwf-160 c24 22 50 ach-056

I'll go through all list in the manual.

Then the schematics says ACH-444 for C23, 24. That's common.
Anyway, those are green "Muse" caps, replacement is Nichi UES.
Please, use top quality audio caps for GWF-160 feedback C13,14: Nichicon UKZ or Elna RFSII (Mouser started stocking Elna RFS). Same caps for GWH-168 C3,4 and Nichicon UES for C9, 10.
 
Thanks hennessy,

Here is the completed capacitor list from the manual and schematic, with Pioneer stock numbers.

a-88x gyw-110 c19 1000p CQSXA-102J 160
a-88x gyw-110 c12 1000p CQSXA-102J 160

a-88x chassis direct c3 10000 71 ACH-106
a-88x chassis direct c4 10000 71 ACH-106
a-88x chassis direct c5 10000 71 ACH-106
a-88x chassis direct c6 10000 71 ACH-106

a-88x gwf-160 c1 220p CMA-221J 500
a-88x gwf-160 c2 220p CMA-221J 500
a-88x gwf-160 c3 100p cea-101J 500
a-88x gwf-160 c4 100p cea-101J 500
a-88x gwf-160 c5 (1200p/100V) ACE-086
a-88x gwf-160 c6 (1200p/100V) ACE-086
a-88x gwf-160 c7 0.12 ACE-095
a-88x gwf-160 c8 0.12 ACE-095
a-88x gwf-160 c9 (0.033/100V) ACE-094
a-88x gwf-160 c10 (0.033/100V) ACE-094
a-88x gwf-160 c11 (1200p/100V) ACE-086
a-88x gwf-160 c12 (1200p/100V) ACE-086
a-88x gwf-160 c13 1000 25 ceya-102M25
a-88x gwf-160 c14 1000 25 ceya-103M25
a-88x gwf-160 c15 47p CMA-470J 500
a-88x gwf-160 c16 47p CMA-470J 500
a-88x gwf-160 c17 (0.01/100V) ACE-067
a-88x gwf-160 c18 (0.01/100V) ACE-067
a-88x gwf-160 c19 100p cea-101J 500
a-88x gwf-160 c20 100p cea-101J 500
a-88x gwf-160 c21 100p cea-101J 500
a-88x gwf-160 c22 100p cea-101J 500
a-88x gwf-160 c23 22 50 ach-456
a-88x gwf-160 c24 22 50 ach-456
a-88x gwf-160 c25 (0.01/100V) ACE-066
a-88x gwf-160 c26 (0.01/100V) ACE-066
a-88x gwf-160 c101 220 50 ceya-221M50
a-88x gwf-160 c102 220 50 ceya-221M50
a-88x gwf-160 c103 220 50 ceya-221M50
a-88x gwf-160 c104 220 50 ceya-221M50
a-88x gwf-160 c105 2.2 50 cexa-2R2M50
a-88x gwf-160 c106 2.2 50 cexa-2R2M50
a-88x gwf-160 c107 2.2 50 cexa-2R2M50
a-88x gwf-160 c108 2.2 50 cexa-2R2M50
a-88x gwf-160 c109 470p CQSXA- 471J 160
a-88x gwf-160 c110 470p CQSXA- 471J 160
a-88x gwf-160 c111 470p CQSXA -471J 160
a-88x gwf-160 c112 470p CQSXA -471J 160
a-88x gwf-160 c113 330 50 ceya-331M 50
a-88x gwf-160 c114 330 50 ceya-331M 50
a-88x gwf-160 c115 47p CMA- 470J 500
a-88x gwf-160 c116 47p CMA -470J 500
a-88x gwf-160 c117 47p CMA -470J 500
a-88x gwf-160 c118 47p CMA -470J 500

a-88x gwh-168 c15 CQSXA -221J 160
a-88x gwh-168 c1 CQSXA- 561J 160
a-88x gwh-168 c2 CQSXA -561J 160
a-88x gwh-168 c3 330 50 ceya-331M 50
a-88x gwh-168 c4 330 50 ceya-331M 50
a-88x gwh-168 c7 CQSXA -102J 160
a-88x gwh-168 c8 CQSXA- 102J 160
a-88x gwh-168 c9 470 25 ACH-455
a-88x gwh-168 c10 470 25 ACH-455
a-88x gwh-168 c11 15p CMA- 150J 500
a-88x gwh-168 c12 15p CMA -150J 500
a-88x gwh-168 c13 15p CMA- 150J 500
a-88x gwh-168 c14 15p CMA- 150J 500
a-88x gwh-168 c15 560p CQSXA -221J 160
a-88x gwh-168 c16 560p CQSXA- 221J 160
a-88x gwh-168 c17 (0.01/100V ACE-066
a-88x gwh-168 c18 (0.01/100V ACE-066
a-88x gwh-168 c19 68p CMA -680J 500
a-88x gwh-168 c20 60p CMA -680J 500
a-88x gwh-168 c21 68p CMA -680J 500
a-88x gwh-168 c22 60p CMA -680J 500
a-88x gwh-168 c23 150p CQSXA -151J 160
a-88x gwh-168 c24 150p CQSXA -151J 160
a-88x gwh-168 c25 100p CMA -101J 500
a-88x gwh-168 c26 100p CMA -101J 500
a-88x gwh-168 c27 100p CMA- 101J 500
a-88x gwh-168 c28 100p CMA 101J 500
a-88x gwh-168 c29 220 63 ACH-454
a-88x gwh-168 c30 220 63 ACH-454
a-88x gwh-168 c31 220 63 ACH-454
a-88x gwh-168 c32 220 63 ACH-454
a-88x gwh-168 c33 47 63 ACH-452
a-88x gwh-168 c34 47 63 ACH-452
a-88x gwh-168 c35 47 63 ACH-452
a-88x gwh-168 c36 47 63 ACH-452

a-88x gwh-169 c37 2.2 100 ceanp-2R2M 100
a-88x gwh-169 c39 (0.1/100V) ACE-067
a-88x gwh-169 c41 (0.1/100V) ACE-067
a-88x gwh-169 c43 470 10 cea-471M 10L

a-88x gwh-170 c38 2.2 100 ceanp-2R2M 100
a-88x gwh-170 c40 (0.1/100V) ACE-067
a-88x gwh-170 c42 (0.1/100V) ACE-067
a-88x gwh-170 c44 470 10 cea-471M 10L

a-88x gwg-186 c1 2.2 50 cexa-2R2M50
a-88x gwg-186 c2 2.2 50 cexa-2R2M50
a-88x gwg-186 c3 10 50 cea-100M 50L
a-88x gwg-186 c4 10 50 cea-100M 50L
a-88x gwg-186 c5 0.1 CQMA -104J 50
a-88x gwg-186 c6 0.1 CQMA- 104J 50
a-88x gwg-186 c7 10 50 cea-100M 50L
a-88x gwg-186 c8 10 50 cea-100M 50L
a-88x gwg-186 c9 10 50 cea-100M 50L
a-88x gwg-186 c10 10 50 cea-100M 50L
a-88x gwg-186 c11 0.0047 CQMA- 562J 50
a-88x gwg-186 c12 0.0047 CQMA- 562J 50
a-88x gwg-186 c13 1.5 50 cea-1R5M 50L
a-88x gwg-186 c14 1.5 50 cea-1R5M 50L
a-88x gwg-186 c15 100p CCDSL- 101J 50
a-88x gwg-186 c16 100p CCDSL- 101J 50
a-88x gwg-186 c17 10 50 cea-100M 50L
a-88x gwg-186 c18 10 50 cea-100M 50L

a-88x gwr-203 c1 100 100 cea-101M 100L
a-88x gwr-203 c2 3.3 50 cea-3R3M 50L
a-88x gwr-203 c4 33 16 cea-330M 16L
a-88x gwr-203 c5 10 50 cea-100M 50L
a-88x gwr-203 c6 10 50 cea-100M 50L
a-88x gwr-203 c7 470 50 ceya-471M 50
a-88x gwr-203 c8 470 50 ceya-471M 50
a-88x gwr-203 c9 470 50 ceya-471M 50
a-88x gwr-203 c10 470 50 ceya-471M 50
a-88x gws-521 c1 (0.22/100V) ACE-075
a-88x gws-521 c2 (0.22/100V) ACE-075
a-88x gws-522 c3 120p CQSXA-121J 160
a-88x gws-522 c4 120p CQSXA-121J 160
 
This is a whole new animal....

"special foil and electrolyte", and THEN:

the cex is tin plated oxygen-free copper wire leads

the cey is tin plated copper wire leads

it will take some (extensive?) research to come up with appropriate substitutes.

I can understand silmic, non-iron leads and "magnetic distortion", and forgive "special foil and electrolyte", but oxygen free copper on a conventional PC board? marketing...
Like interspersing garden hose and stainless steel piping.

These are arguments I WILL NOT get into. :nono:
 
hennessy, can you help match match up substitute stock numbers from the list I provided. I can see that you have had more experience at rebuilding A-88X then me which is 0. Any replacement stock numbers at this point would be great. Thanks
 
Dumb but important question: MadeMine, are you IN the USA? WHERE (roughly) are you?

as to the list, it's taking a bit of work, and I will finish it as soon as I am able. The political issue I am involved in is coming to a head, and now it has come down to a battle between the two most powerful politicians in the state and we are scrambling to avoid being crushed between them and snatch good things out of the path of the collision.
 
Good, the USA, Mouser parts numbers :D

Re: Colorado, (was in Denver area once) beautiful state, exciting hunting...
 
To compile BOM list it would take me probably the same time as to do the recap:D.
I do not use BOMs for what I do. I use Excel to keep track of my inventories of Op-Amps, capacitors, resistors, diodes, zeners, transistors, pots etc. If I see some values going low, I order them. Some things @Mouser are 2-3 times cheaper if you bulk order them. Especially all those new batches of caps coming in with absurd price hikes.
Most of the caps can deviate from original values. Modern caps are higher in voltage values being the same size. Therefore, you can order higher voltage rated.

I.e. on voltage amp board (the one in the middle) the regulator is stacked with Muse 220 and 47 caps at 63V and 85 C rating. Instead of those you can use Nichicon UHE, UPW, UKA, UKL ANA(105 Deg), Panasonic FR, FM, FC. UHE and FC come in regular diameter and narrow (prefix L, download the spec pdf). The working voltage is close to 60V in our case, therefore a capacitor rated at 100V is preferable. If you can squeeze a 330uF/100V and 100uF/100V there - it is fine.

All caps on the power board (upside down one at the bottom) should be 105 rated.
Just use the guidelines @ post #2.
Don't forget those resistors and zeners. For zeners you can search for Vishay BZX (55 and 85) series at 2% tolerance.
 
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