Sony TA-F6B Resto

[thefragger]

This is my fixer-upper. I bought it on eBay a couple months back as a complete parts-only unit. The guy described it looking much worse ('badly scratched face,' 'rusted top,' etc...) that what it actually is (little bit of rust on top, maybe one scratch a half-inch long); I think it looks great! Being in my graduating year, I never had much time to work on it.

What I did do was find that a thermal fuse had opened and replacing that brought the amp to life! Since then it's been sitting...

... Until now. I'm a stamped-and-certified Mechanical Engineering Technologist! So today I took to tearing that amp down. It's pretty filthy inside and I think at some point something tried to build a nest under the amplification circuit. It's bad.

My plan is to tear everything out, hose everything down, clean out the interior rust, patch up the top panel rust, and do a full TOTL recap. Polish the casing to a lustrous shine and plant it at the centre of my system.

This will be my biggest project in a long while (too long), my pride and joy.

I figure I'll update this thread as a work log. Wish me luck!

[thefragger]

These photos are from today's teardown.


First the nudie,


Slowly breaking it down on my 'bench,'


Amp board out, literally an 1/8" of dust,


Water seepage?


Dinged up heatsink...

[tri-comp]

The one thermal fuse in this amp. is in the soft-start circuit.
Strange that it would blow as it's only used for a couple of seconds until the switched-mode power-supply is up and running. Then it's shorted out by a relay. Check that relay in any case!
I think that you should have a look at the schematic's. PM me with your e-mail address for a free pdf-copy.

A sound advice would be to ABSOLUTELY DO A RECAP of the switched-mode power-supply.
I had a lot of 'fun' with something similar in a TA-N86 / Class-A amp. until I finally did the full re-cap.
TA-N86 -> http://www.thevintageknob.org/SONY/s...N86/TAN86.html

rgds,

/tri-comp

[Stoffie]

Yep, definitely a good idea to recap the PLPS with 105C caps...

I have four amps with PLPS' waiting for such a treatment.

Good luck! Nice amp btw! Reminds me of the TA-F7B I have, also 1cm of dust and crap inside, water leakage etc... but it is shining now!

[thefragger]

Originally Posted by tri-comp

The one thermal fuse in this amp. is in the soft-start circuit.
Strange that it would blow as it's only used for a couple of seconds until the switched-mode power-supply is up and running. Then it's shorted out by a relay. Check that relay in any case!
I think that you should have a look at the schematic's. PM me with your e-mail address for a free pdf-copy.

Get this-- there is no relay. Dr*Audio told me the same thing, but the PCB has no relay on it, nor does it look like one was ever installed. I'll get you my email address, but I've bought the service manual already.

A sound advice would be to ABSOLUTELY DO A RECAP of the switched-mode power-supply.
I had a lot of 'fun' with something similar in a TA-N86 / Class-A amp. until I finally did the full re-cap.
TA-N86 -> http://www.thevintageknob.org/SONY/s...N86/TAN86.html

That's the plan! When I was testing it after replacing that thermal fuse the sound would work for a while then fade away after about an hour. I'm hoping that the full re-cap will fix that.


Cheers tri-comp.
Philip.


P.S. That TA-N86 is a pretty sweet looking amp!!

[thefragger]

What if I can't find / get / afford high-frequency caps for the power supply? Would regular low-impedance work in a pinch, or is it blasphemy?


Philip.

[thefragger]

Alright, I've completely disembodied the electronics and I'm left with a very dirty, dusty, and rusty chassis. I've started to sand down the rust and I'm left with shiny, bare metal. I really, really don't want it to rust again, at least not for another 30 years. What should I use to seal up the bare metal?

I'll try and get some photos up. Tomorrow.


Philip.

[thefragger]

I picked up the capacitors from Purolator yesterday and got to work into the wee hours of the morning.

Took lots of photos. Will post later.


Enjoying the fruits right now. Really really warm sound. Neil Young's in the other room calling me back.


Cheers!
Philip.

[thefragger]

Black Pastic Rivet Replacements

New Caps (twice the amount that I needed)

PLPS Before, in Progress, and After

[thefragger]

Amp Before, In Progress, and After (the size difference is really, really noticeable)

Old vs. New

Old Parts

Amp in, PLPS in, and All Hooked Up

[thefragger]

Making Some Noise

Very Shiney

Corrosion (?? how can I remedy this?)

Need to Re-Paint the Lettering

Looking Good and Making Itself Known

[Stoffie]

Very nice work! It's been a lengthy process, but seems like it was worth it!

Will be doing the same to my TA-F7B soon, when the parts arrive. Already took care of the switches and pots in the preamp, so a recap is all that is left.

[legal eagle]

Nicely done.
I've always wanted one of those, as that's BY FAR the best looking integrated i've seen. There's quite a lot of those in Europe, but they are pricey, and another integrated will probably push the wife over the edge...

[rsfmotoman]

Nice Work!

That has to be a very satisfying feeling to bring an amp back to life. All I can is resurrect speakers.

Fine job!

[westend]

Nice job. For lght corrosion I use a dilute solution of Phosphoric acid, sold as water softener cleaner or Martin Senour Iron Etch.
Now the caveats: This acid reacts with aluminum and especially anodized aluminum very fast. You have to dilute it and always try an inconspicuous area to test (back of faceplate?). If you don't know anything about chemicals and metal etching, don't bother trying. Your newly rehabed Sony will end up with a lot of wierd stains. Rinse with water after the treatment and keep it away from the meter lenses.
I watched too much "Watch Mr. Wizard" on TV as a kid and have a couple of years of college chemistry and 20+ years of autobody and shipboard painting experience so I kinda know what I'm doing with preparation chemicals. It's not for the faint of heart but will remove oxidation from nearly all metals.

Remember: If you use this you're working with Acid. It will burn your skin and irritate your eyes and lungs. Use precautions.