Should I power this thing up?(I HAVE NO VARIAC)

[kaboom]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Looking at the schematic it does have the varisters on the heat sinks. SV-004. They haven't been made since the seventies and the supplies have been used up. They can be replaced with three diodes in series but it's best just to be careful and don't hurt the ones you have. Their wires are solid not stranded and very fragile.

Those are thermistors, not varistors.

The other ones are STV-3s. Just use 3 1N4004s in series, but be careful mounting them! Shorts to the heatsink are bad. As in "blow the amp up" bad. Had to do this in a Sansui 4000 a few years ago. Unit was "gotten to" and both channels blew up. Had to rebuld both driver boards with modern components. Only one board had a blown trace- a simple jumper fixed that. I used thermal epoxy to mount the bias diode assemblies to a heatsink on each driver board.


The Sanyo 1056 does not have thermistors in the amp, only STV-3s. Look at the schematic.

If you realize a problem is a challenge and not the end of the world you'll do fine in life. Or at least better.

It's actually one of the easier units to work on, just maybe not the thing for a beginner. Finished a Fisher 500T recently- what an adventure... Those stupid "flat pack" (think SIP TO-92) transistors on the autoscan board were bad.

Shotgunned all of them, autoscan repaired.

Was a bear to align, since the trimmer caps in the front end module were this close to coming apart- got lucky and got it much better.

IF alignment wasn't too bad, but had to "improvise" with sig gen and 2nd harmonic of xtal oscillator- remember, front end was slightly off, even after I got it better. MPX was okay, thank goodness- I don't have an MPX gen.

Power amp board pulled, resoldered, washed. Driver transistors got new thermal compound, new zener for derived voltage, larger/safer resistors for driver transistors- originals were marginal. 21195/96 output transistors.

Power supply upgraded- bigger diodes, larger caps, and minor-rail reg transistor replaced with one having greater SOA, and put on a larger heatsink. Entire board resoldered, cracks epoxied, board washed.

Tone control and autoscan boards also resoldered and washed.

All controls cleaned, all caps replaced. The only thing in that unit untouched was the AM RF board. The ferrite loopstick was "lost" years ago; decision by owner was made to abandon AM.

Also cleaned up wiring from AC socket to switch/transformer, and from transformer to PS board- also added the full compliment of PS fuses.


TG- yours is an easy unit to work on, but if you get frustrated and/or "make do" with the wrong tools, you'll only make things hard for yourself.

Obtain a proper soldering iron

That right there is ~$80 to budget, for a W60P. You'll also need a bigger tip than what comes with it. Something like a 700 degree, 3/32 "screwdriver" tip. Or closer to ~$180-200 for a "station."

Don't drop a dollar to pick up a dime- meaning, don't go cheep on soldering equipment. And, for your sanity, do NOT get a cheep aoyoue thing- if they were a power supply, they'd make Deers look like NASA-spec stuff.

AVOID AOYOUE like the plague.

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Looking at the schematic it does have the varisters on the heat sinks. SV-004. They haven't been made since the seventies and the supplies have been used up. They can be replaced with three diodes in series but it's best just to be careful and don't hurt the ones you have. Their wires are solid not stranded and very fragile.

[kaboom]

Re: Should I power this thing up?(I HAVE NO VARIAC)

is it bad when I can drive intercom speakers that use a transformer and not have a problem?

Drive the VC directly.

Also, how can I remove the non-soldered wires from the boards w/o cutting them?

Those wire-wrap posts? Desolder them, much easier. All too often when unwrapping them, the wires break. If there's not much to begin with, you'll be in for a treat stripping them. And you won't be able to wrap the posts w/o a wirewrap tool. Just heat the posts on the solder side and pull them out.

You need a good temp controlled iron. Even a weller magnestat will do. And some small needlenose pliers. Be gentle, or you'll be ripping traces.


Ignore anything about "audio grade" caps- you want hi temp ones for the life of the unit. The ones I specified are just fine. I've used tons in Yamahas, Sansuis, Kenwoods, etc.

hello?

Not all of us "play computer" all day long...

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Don't bother checking the old caps unless you just want to. They are 40 years old and due for replacement. Use Nichicon KL and PW series. KL in the audio path, usually those caps will be sky blue or orange. PW for everything else.

Since Mouser has them in almost every size you can replace them with same size in most cases.

You can check the schematic for any problems. One of mine was designed for 117 volts and uses a zener diode in the feedback circuit to the power supply. When the voltage gets too high the zener reverse biases and bleeds off the excess to ground. With a 124 volt line here and now they work pretty hard so I went with a bigger diode.

Look for 2SA726 transistors, replace with ksa992's, replace 1313's with 1845's.

Change the heat sink grease with gc chemicals z9, it's silicone base and mil spec.

Don't touch any pots on the tuner board. You'll need a full alignment if you do.

Some manufacturers put a temp sensing diode on the heat sink. They are unobtanium now so look for them and be careful with them.

That's about it with a good cleaning of course.

By the way, the service manual is here http://www.hifiengine.com/manual_lib.../rs-1056.shtml . Just join up and the download is free.

[TechGeek]

Re: Should I power this thing up?(I HAVE NO VARIAC)

OK, I've come up with a repair/partial restoration plan:

1. Remove stripped screw
2. Remove low-level tone control board
3. Remove/Loosen all boards to be recapped
4. Obtain list of caps to replace
5. Obtain list of caps to replace WITH
6. Obtain a proper soldering iron
7. Obtain solder wick
8. Recap what needs to be recapped
9. Obtain a capacitance meter
10. Obtain an ESR meter
11. Check capacitance and ESR of old caps(just for fun)
12. Blow up old caps that have high ESR/low capacitance
13. DONE

Is this good? Also, what caps should I use on the low-level tone control boards? Thanks.

[diif]

Re: Should I power this thing up?(I HAVE NO VARIAC)

no, they make a mess....tiny metal shards everywhere, high speed, to much risk of damage if you slip.
Follow the advice of the man that's been dealing with stripped and cross threaded fasteners IIRC longer than you've been alive. I know I have, and his list is sound and of course in order of ease/mess/time.

[dmill89]

Re: Should I power this thing up?(I HAVE NO VARIAC)

could I use a Dremel to make a solid line all the way across the screw and then use a flat-head screwdriver to remove the screw?

Yes as long as you are careful.

[dmill89]

Re: Should I power this thing up?(I HAVE NO VARIAC)

I have a 1995 and I think it's a Sanyo, too...

It is, Fisher was owned by Sanyo from 1975-2010 (prior to that it was owned by Emerson from 1969-1975, Fisher was an independent company from 1937-1969) when Sanyo itself was purchased by Matsushita/Panasonic (Matsushita officially changed their name to Panasonic Corporation in 2008), Panasonic still owns the rights to the Fisher brand but phased it out in 2012.

[TechGeek]

Re: Should I power this thing up?(I HAVE NO VARIAC)

could I use a Dremel to make a solid line all the way across the screw and then use a flat-head screwdriver to remove the screw?

[ReeceyBurger123]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Carefully....and as my gran used to say "good manners cost nothing"

The way I was taught was a smack round the head sounds like someone never got that

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Several ways. If you can get a pair of lock pliers on it, turn it out. If you have an easy out. use that. Or drill the head off. Use a drill bit bigger than the head of the screw and drill off the head. Just be careful and take your time.

[diif]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Carefully....and as my gran used to say "good manners cost nothing"

[TechGeek]

Re: Should I power this thing up?(I HAVE NO VARIAC)

managed to strip a screw on the low-level tone control board... how do I get it out?

[ReeceyBurger123]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Fucking rude

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

If you realize a problem is a challenge and not the end of the world you'll do fine in life. Or at least better.

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

It can't be that hard. Pioneer is bad with that wire wrap and I managed to get the boards lifted an inch so I could get to the bottom of the boards. It takes skill and patience but you knew that. Not everything in life is easy. Work on cars or airplanes enough and you learn that. Sometimes where you need to go is just barely big enough to get a hand into but not big enough to see in it and it's full of sharp edges so you pretty much pull out a bloody stump when your done.

[goontron]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Lose the temper before you fuck something up in a childish rage?

[TechGeek]

Re: Should I power this thing up?(I HAVE NO VARIAC)

well, what am I going to do when I have to RECAP THE FLIPPING STEREO!?!?!?!?

Unsolder every last pin?

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

First problem is originality, it's hard to wire wrap if you don't know how. Takes practice just like soldering. Second is keeping track of where each wire goes. One miswire can cost you the whole project or at least a lot of trouble.

[rhomanski]

Re: Should I power this thing up?(I HAVE NO VARIAC)

Temper temper young man. I thought I did answer. Look up wire wrap. Don't cut those wires at all. Just move the board around as easy as you can because they are solid core and will break. If you absolutely have to remove one, unsolder the pin it's attached to from the board.