Help needed to recap my Sony TA707ES...

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youknowyou

youknowyou

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Joined 2014
#1
hi everyone, I want to recap my Sony ta 707es integrated amp.

If I understand correctly, all the caps that need replacing are the electrolytic and I can let all the film and ceramic caps as is?

I do not use the preamp section or the phono stage so no need to recap those sections as im only using the amp via ''direct mode''.

I have drafted what I think I need to change in order to replace every critical cap. can anyone confirm that im not missing any


47uf - 63v: 5 units

22uf - 100v: 4 units

100uf - 63v: 4
1000uf - 63v: 4
220uf - 50v: 1
47uf - 25v: 8
1uf - 100v: 1
470 uf - 63v: 1
330uf - 63v: 2
4.7uf - 63 v: 8
1 uf- 50v: 1
47uf - 16v: 3
2200 uf - 16v: 1
22uf - 63v: 3
10uf - 50: 4
330uf - 10v: 1

4 main PSU caps:
c701 8200 uf - 63v
c752 18 000 uf - 63v
c702 8200 uf - 63v
c752 18 000 uf - 63v

if anyone is kind enough to help me, id be glad!
cheers
 
#2
Ayya said:
I want to recap my Sony ta 707es integrated amp. all the caps that need replacing are the electrolytic.
I do not use the preamp section or the phono stage so no need to recap those sections as im only
using the amp via ''direct mode''.
Click to expand...

That's right, unless some of the other electrolytics (or tantalums) are actually failing.
Electrolytics bulge or leak, and tantalums burn up, often charring the board.
 
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#3
ive been recommended to bypass many switches in ''direct mode''


if I look at the schematic in direct mode, should I bypass S102?
I further see that the direct mode is not so direct, it passes threw muting, source direct switch, stereo/mono, ect.

can someone draw on the schematic the best way to simplify the ''direct input'' as I only need the direct input--main amp-- volume control in the signal path!

thanks a lot
 
#4
Ayya said:
ive been recommended to bypass many switches in ''direct mode''


if I look at the schematic in direct mode, should I bypass S102?
I further see that the direct mode is not so direct, it passes threw muting, source direct switch, stereo/mono, ect.

can someone draw on the schematic the best way to simplify the ''direct input'' as I only need the direct input--main amp-- volume control in the signal path!

thanks a lot
Click to expand...

Do not butcher the amp needlessly. Yes it is yours and you can do whatever you please but misguided attempts at 'audiophiling' amplifiers LOWER your amps's worth. Especially be wary of 'recommendations' to modify internal wiring which show obvious lack of knowledge how the amp is even structured.

The F707 has no preamp section, it is a high cain single amp design, ell the gain is handled in the power amp, except for additional gain and RIAA EQ in the case of the phono input. There is a block diagram in the service manual, which also shows the signal routing. The fact that you can't read it and are asking someone else to do it here, is already cause for alarm.
That being said: Once the direct switch is engaged, a lot of the parts are out of the circuit and already are bypassed so no need to 'bypass switches'. The only one that would merit something like this is the actual direct sw, but doing it properly means removig the SW or cutting tracks on the PCBs. One word: DONT. Just clean it properly and leave it there in it's direct position. And even this will be a challenge, as proper cleaning requires removing and disassembling the switch. One wrong move - no switch, and no spares = cosmetically challenged amp that was just fine before.
Again, i would suggest studying that block diagram. It shows some interesting things to do with direct and processor inputs - these bypass quite a lot of the switching network, and are the shortest path to the volume pot - and most users have no idea of this cause they could not be bothered to read the instructions.

Finally, rebuilding an amp is not just 'replacing caps'. There are many types that differ both electrically and mechanically and you need to fit either exact or same/improved spec replacements (and know which improved specs actually make a difference in that part of the circuit), of which you will not be able to find some as they are custom made - first and foremost the main PSU caps. Even standard caps come in different sizes, and Sony used their own with vibration damping applied so the dimensions and contacts are all custom. Having seen attempts at bodging this job in a F707, F808 and F870, I am tempted to superglue the palms of the persons that did it, onto their face over their eye sockets.
DON'T DON'T DON'T do jobs which you have no idea about on proper amps, if you really want to learn, start with a junk amp.

Knowing what caps to change and/or upgrade and where, including the mechanics of getting to them and fitting them, plus other things that need to be checked and refinished and adjusted, is not an easy job even for someone with a lot of experience if you want it done right and the results being at least as good as the original (and not actually worse or terminal, as in: dead amplifier). This is not a 'pick them caps out from a catalog' job - you need to look at what is in there first, and UNDERSTAND WHY it is in there. Not to mention required tools, soldering and de-soldering technique, etc.
 
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#7
It is very much advised that the technician use an ESR meter to determine which caps are actually faulty - depending on how many hours and where it's been used, most of them might end up being perfectly fine. These units should have had good parts quality and aren't so old that I'd advise shotgunning them.
 
#8
ilimzn said:
first and foremost the main PSU caps. Even standard caps come in different sizes, and Sony used their own with vibration damping applied so the dimensions and contacts are all custom. Having seen attempts at bodging this job in a F707, F808 and F870, I am tempted to superglue the palms of the persons that did it, onto their face over their eye sockets.
DON'T DON'T DON'T do jobs which you have no idea about on proper amps, if you really want to learn, start with a junk amp.

Knowing what caps to change and/or upgrade and where, including the mechanics of getting to them and fitting them, plus other things that need to be checked and refinished and adjusted, is not an easy job even for someone with a lot of experience if you want it done right and the results being at least as good as the original (and not actually worse or terminal, as in: dead amplifier). This is not a 'pick them caps out from a catalog' job - you need to look at what is in there first, and UNDERSTAND WHY it is in there. Not to mention required tools, soldering and de-soldering technique, etc.
Click to expand...
hi
im about to order the replacement electrolytic caps.

from your post here, I gather I shouldnt replace the main PSU caps?
the two mains psu caps in the sony ta 707 are: 18,000uf - 63v and 8,200uf - 63v. their ESR measure just fine, should I replace them or let them be?
 
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