Found a Sansui G-971

[Vince1966]

Today I picked up a G-971 along with a bunch of other stuff, original owner purchased it and a lot of other stuff in Germany and has decided to get rid of it. Price was more than fair for all of it but my main interest was in the G971. He said it developed static in one channel and stored it away for 20+ years.

first thing I did was open it up to look for any issues but found a unmolested interior. Checked all the fuses, nothing looked cooked. Dim bulb came on bright then dimmed down, came out of protect and all lights work, tuner display works. No sound, checked a few other sources no sound. Put the DMM on the fuseable resistors on the amp boards and they are open. So I see why there is no sound. Downloading the service manual now.

is there any other problem areas to address when I dig into this girl or is it just the usual Sansui issues?
I have repaired a few G’s the 5700, 7000, and 4000. Looking forward to adding this beast to the lineup.

BTW, anyone need 4 kenwood KL999x speakers? Part of the package as well as a KR6030, Sansui RA900, and a pile of other bits.

 

[DB-7]

I like the black face plate on those.

 

[ivandezande]

Also check all the resistors below the heatsink on the driver boards. I've had those die without showing signs.

 

[Vince1966]

Also check all the resistors below the heatsink on the driver boards. I've had those die without showing signs.

spent a few hours today on it, pulled both driver boards. All the resistors below the heat sink checked good. The 2 fuse resistors are bad 6.8m ohm and 1.9m ohm on one board. Also all the 330uf caps are leaking out of the tops on 3, the heat shrink feels like it has goose bumps. Placed an order for all the parts today. So first up is the 150ohm resistors and 4 330uf caps. Then I will power it up on Dim bulb to be sure that’s all it needed before recapping the boards and getting rid of the known to go bad parts.
Also the VD1212 diodes, replace with series pair of 1n4148’s if I remember correctly? There are 4 in this unit by my count. Anything else to address?

 

[ivandezande]

spent a few hours today on it, pulled both driver boards. All the resistors below the heat sink checked good. The 2 fuse resistors are bad 6.8m ohm and 1.9m ohm on one board. Also all the 330uf caps are leaking out of the tops on 3, the heat shrink feels like it has goose bumps. Placed an order for all the parts today. So first up is the 150ohm resistors and 4 330uf caps. Then I will power it up on Dim bulb to be sure that’s all it needed before recapping the boards and getting rid of the known to go bad parts.
Also the VD1212 diodes, replace with series pair of 1n4148’s if I remember correctly? There are 4 in this unit by my count. Anything else to address?

Sounds about right as far as just getting it going again.
Maybe the trimmers, I remember them being not so great.

 

[Vince1966]

Fuseable resistors replaced along with the leaking 330 caps and small cap. Installed new trimmers, one looked a little burned. Fired up but went into protection, DC was high in the right, was able to get adjust close to zero and checked, adjusted bias. Volume and balance needs a good cleaning. The rest of the parts will be here in a few days for a proper refurb. Excited about getting this one redone. Anyone recommend a good cleaner other than windex that’s safe on the lettering and anodizing?

 

[Vince1966]

And it’s running, just a few more things to do but it’s sounding nice. Need to clean the selector switch again but so far so good.

 

[slow_jazz]

Congrats.

 

[Sansuiman]

That is one imposing looking receiver. Not sure what it ls exactly, but the presentation of the G-9700 (971) in black is somehow more dramatic than previous models to get that treatment, like he 990DB and QRX-999. And both of the latter are quite physically large, so it isn't just the dimensions in play.

At any rate, you did well picking that beast up and getting it back in shape. Massive power on reserve, and good looks to boot. As the bridge model between the G-9000 and 9900Z, I always thought these had a killer aesthetic, while holding onto pretty serious build quality that was largely gone by the time the 9900Z took its place.

 

[Vince1966]

it truly is a big receiver, thats my 9090db to the left, makes it look small. I really like the look of the black face and silver knobs. luckily the bonnet is in good shape as well. the original owner had it stored away and protected for a long time.

 

[Vince1966]

Just wanted to verify the bias test points, attach probes to the emitter terminals of tr02 and tr03. No mention of +- and adjust to +-5mV, so the range is 0.0 to 10.0 mV. Pictures below….

left channel.



Right channel…