TX-7800 recap list

I haven't seen a thread on recapping the TX-7800, so I sifted through several threads and attempted to build a list of caps required by translating the part numbers from the service manual and by using the Mouser website. The CSV list below should import into Excel. Capacitors are listed in the order they appear in the Service Manual. Please note that this is NOT currently an approved or recommended list, but a starting point.

Edit: I have raised the voltage on some capacitors and corrected several entries that did not need low leakage caps.

Pioneer TX-7800 re-cap,,,,Nichicon UKL = low leakage,,
,,,,,,
Part Number,uF,V,Svc Manual,Notes,Mouser Part Number,
Power Supply (AWR-183),,,,,,
Capacitors,,,,,,
C3,1000,25,CEA 102P 16,Increased Voltage,647-UPW1E102MHD,
C4,1000,25,CEA 102P 16,Increased Voltage,647-UPW1E102MHD,
C5,470,35,CEA 471P 35,,647-UPW1V471MPD,
C6,470,35,CEA 471P 25,Increased Voltage,647-UPW1V471MPD,
C7,100,25,CEA 101P 16,Increased Voltage,647-UPW1E101MED,
C8,100,25,CEA 101P 16,Increased Voltage,647-UPW1E101MED,
Transistors,,,,,,
Q1,,,2SD712-D,,512-KSC2073TU,
Q2,,,2SC945A-Q,,512-KSC2383YTA,
,,,,,,
,,,,,,
Tuner (GWE-111),,,,,,
C13,4.7,35,CEA 4R7P 35,,647-UPW1V4R7MDD,
C99,4.7,35,CEA 4R7P 35,,647-UPW1V4R7MDD,
C16,22,25,CEA 220P 16,Increased Voltage,647-UPW1E220MDD,
C32,3.3,50,CEA 3R3P 50,,647-UPW1H3R3MDD,
C57,3.3,50,CEA 3R3P 50,,647-UPW1H3R3MDD,
C98,3.3,50,CEA 3R3P 50,,647-UPW1H3R3MDD,
C34,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C58,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C66,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C73,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C83,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C84,10,25,CEA 100P 16,Increased Voltage,647-UPW1E100MDD,
C36,100,25,CEA 101P 6,Increased Voltage,647-UPW1E101MED,
C39,1,50,CEANL 010M 50,Low Leakage,647-UKL1H010MDDANA,
C47,1,50,CEANL 010M 50,Low Leakage,647-UKL1H010MDDANA,
C50,1,50,CEANL 010M 50,Low Leakage,647-UKL1H010MDDANA,
C41,220,25,CEA 221P 16,Increased Voltage,647-UPW1E221MPD,
C68,220,25,CEA 221P 16,Increased Voltage,647-UPW1E221MPD,
C42,470,25,CEA 471P 16,Increased Voltage,647-UPW1E471MPD,
C43,10,16,CEANL 100M 16,Low Leakage,647-UKL1C100MDDANA,
C52,10,16,CEANL 100M 16,Low Leakage,647-UKL1C100MDDANA,
C53,10,16,CEANL 100M 16,Low Leakage,647-UKL1C100MDDANA,
C67,33,25,CEA 330P 16,Increased Voltage,647-UPW1E330MDD,
C48,6.8,50,CEANL 6R8M 50,Low Leakage,647-UKL1H6R8KDDANA,
C54,0.33,50,CEANL R33M 50,Low Leakage,647-UKL1HR33KDDANA,
C56,0.33,50,CEANL R33M 50,Low Leakage,647-UKL1HR33KDDANA,
C61,47,25,CEA 470P 16,Increased Voltage,647-UPW1E470MDD,
C63,4.7,25,CEANL 4R7M 25,Low Leakage,647-UKL1E4R7MDDANA,
C69,4.7,25,CEANL 4R7M 25,Low Leakage,647-UKL1E4R7MDDANA,
C64,47,16,CEA 470P 10,Increased Voltage,647-UPW1C470MDD,
C65,2.2,50,CEA 2R2P 50,,647-UPW1H2R2MDD,
C46,1,50,CEA 010P 50,,647-UPW1H010MDD,
C74,1,50,CEA 010P 50,,647-UPW1H010MDD,
C75,1,50,CEA 010P 50,,647-UPW1H010MDD,
C79,1,50,CEA 010P 50,,647-UPW1H010MDD,
C80,1,50,CEA 010P 50,,647-UPW1H010MDD,
C92,1,50,CEA 010P 50,,647-UPW1H010MDD,
C103,1,50,CEA 010P 50,,647-UPW1H010MDD,
C105,1,50,CEA 010P 50,,647-UPW1H010MDD,
C76,100,25,CEA 101P 16,Increased Voltage,647-UPW1E101MED,
C77,0.1,50,CEANL 0R1M 50,Low Leakage,647-UKL1H0R1MDDANA,
C93,220,10,CEA 221P 6,Increased Voltage,647-UPW1A221MED,

I know that it's delicate work to recap a tuner, especially as a first project. I actually bought a low cost beater TX-7800 to practice on before attempting on the "A-Grade" one.

If anyone has experience recapping this tuner, I would appreciate your looking over the list. Also, I would like to avoid a realignment, at least initially. Is there a reasonably simple rule of which sections of the tuner to avoid recapping? My initial plan is to start with the power supply board (to include the transistors listed) and move on to the tuner board, testing after each change to see if I've hosed things.

Thanks for any help you may offer. I'm not afraid to forge ahead, but I would like to avoid at least the most basic of mistakes. I will report on progress regardless.

BuffDriver

I did the electrolytic tuner caps on my SX-1050, SX-780 and a couple other 70's receivers, no audible difference noted doing them one at a time and checking the receiver's tuner AM and FM operation between each one. Results may vary, and it goes against general principles to some, but that's my experience.

When you change them and have success and/or the list gets vetted, let me know and I'll put it in my Recap List thread

Thanks, Marty, and thanks for keeping the recap list. It was a big help while researching the method that others have used to find modern replacements. After reading several of the threads and MarkTheFixer's advice on which brand and series of caps to use, I feel like it's a pretty decent start.

Before ordering anything from Mouser, I'm gonna try to verify the parts visually. Several folks have mentioned that Pioneer has an occasional error in their service manuals.

Cheers,

BuffDriver

I've edited the original list to upgrade the voltage of some of the smaller capacitors. There was also a group of 1uF 50V caps that I mistakenly spec'ed with UKL caps. These now show UPW standard Low Impedance caps.

The order is placed with Mouser and I should begin work on the "practice" tuner in a week or so.

BuffDriver

I'll be watching this thread. I have a TX-7800 that works fine, in mono. Was thinking of a total recap to see if that gets me in stereo. Do you have any problem with either of your 7800's locking into stereo?

sake said:

Do you have any problem with either of your 7800's locking into stereo?

Click to expand...

They both lock stereo okay. My "B" tuner doesn't tune FM as well as the "A" unit, and barely tunes AM at all. I don't really have any hopes that tuning will improve with the recap. I just hope it tunes as well as before!

I believe that FM multiplex decoding happens in the PA1001A IC. You might try searching for a thread that explains how to check that chip. Others will probably chime in soon that a realignment might be necessary to bring back your stereo reception.

In any case, I will let you know how it goes. I expect it to be an adventure. Hopefully I'm not in over my head.

Cheers,

BuffDriver

I always thought, now why do they have a wide/narrow filter for "AM" and not for "FM" too? Pioneer did some strange things.
Your ecap list looks okay. Use UKL for audio signal path and UPW for dc filtering.
C54/56 (0.33uF/50V) could be changed to a film type.
Sansui, usually put small films across all ecaps in the signal path.

I'll be watching this thread. I have a TX-7800 that works fine, in mono. Was thinking of a total recap to see if that gets me in stereo.

Click to expand...

Stereo problem might very well be the ecaps around Q6, C42, 47,48,50 ...

Okay, many apologies for the delay in posting updates. I used the list above with very good results. The tuner is operating better than before, and I achieved my objective of using a beater tuner to practice component replacement.

Here are some before pics:




And some after:





In hindsight, I learned a few things that I will pass along, mostly to newbies like myself who may be tackling a first project.

1. Be ready to use a variety of desoldering techniques. I used a desolder iron ($25 vacuum bulb type), a solder sucker, and desolder wick at various times. Each has its use. Pioneer components can be difficult as they often bend the leads nearly 90 degrees, and it makes it difficult to get a desolder iron in place. Go slow and be patient.

2. Be gentle with the components as you persuade them off the board. I got a bit heavy handed with a couple of capacitors on the power supply board and ended up breaking the pad loose. It took me a while to learn why the unit wouldn't power up. In the process, I replaced the rectifiers and the 14V zener. My voltages are now nearly spot on with the service manual! Lesson learned: always order the extra small components for the power supply. In the end, it's cheaper than a second shipment.

3. I found that just a bit of resin flux applied with a toothpick helped the solder flow quickly onto the new component.

4. In hindsight, I would have used more stacked film caps for less than 2uF; however, MTF's favorite ECQ caps are going obsolete. Also, it was initially unclear as to whether the ECQs could be substituted for the UKL low leakage Nichicons. After reading several threads, I think that they can. Still, these eCaps should last many years.

Thanks for the encouragement! I hope that this project is useful to others who may want to recap this fine tuner.

All the best,

BuffDriver

well done, thx for the pics
yes, to bad ecq-v are going obsolete, there are others available to sub

cheers

thanks. any addition?

buffdriver said:

4. In hindsight, I would have used more stacked film caps for less than 2uF; however, MTF's favorite ECQ caps are going obsolete. Also, it was initially unclear as to whether the ECQs could be substituted for the UKL low leakage Nichicons. After reading several threads, I think that they can. Still, these eCaps should last many years.

Click to expand...

Could you please give part numbers for them?
Also I could not find the complete service manual, could you please share it also?
Thanks.

For the 1uF 50v (multiple), I purchased WIMA caps:
505-MKS2B041001C00KS $0.40

For C54 & C56: .33uF 50v 667-ECQ-V1H334JL $0.33
For C77: .1uF 50v 667-ECQ-V1H104JL no longer in stock at mouser

As for the service manual, I highly recommend Quag West Vintage Manuals. Google that and you will be able to download a very high quality scan for a reasonable price.

Cheers, and good luck!

BuffDriver

buffdriver said:

For the 1uF 50v (multiple), I purchased WIMA caps:
505-MKS2B041001C00KS $0.40

For C54 & C56: .33uF 50v 667-ECQ-V1H334JL $0.33
For C77: .1uF 50v 667-ECQ-V1H104JL no longer in stock at mouser

As for the service manual, I highly recommend Quag West Vintage Manuals. Google that and you will be able to download a very high quality scan for a reasonable price.

Cheers, and good luck!

BuffDriver

Click to expand...

Thank yoı, is 667-ECQ-V1H104JL suitable for the C77 or could you suggest another one? Thanks again.

merkan said:

Thank yoı, is 667-ECQ-V1H104JL suitable for the C77 or could you suggest another one? Thanks again.

Click to expand...

Yes, it matches the spec that MTF recommends for small electrolytic replacements: Panasonic ECQ (stacked film). These are becoming more difficult to find, as they are end-of-life. You may be able to find another source besides Mouser.

buffdriver said:

Yes, it matches the spec that MTF recommends for small electrolytic replacements: Panasonic ECQ (stacked film). These are becoming more difficult to find, as they are end-of-life. You may be able to find another source besides Mouser.

Click to expand...

actually since it is not available in mouser I was asked another one but I think I copied wrong, could you please check these?
598-DSF050J
505-MKS2.1/63/10
647-QYX1H104KTP

I placed the order,
for C54 and C56 667-ECQ-V1H334JL
for C77 505-MKS2.1/63/10
for C46 C74 C75 C79 C80 C92 C103 C105 505-MKS2B041001C00KS
Then I realized C39 C47 and C50 are also 1uf should they be film also?

Hey Buffdriver...do you still have that beater board? mine is toast...I would gladly buy it from you!