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Sony's 'Big One'

OK got it!

Big thanks to Elroy for ensuring its safe (and fast!) journey to me this weekend.

Hooked it up, sounds nice and looks even better. Pics didn't even do this one justice.

So I have a question about setting the bias. I have the service manual, and it shows for DC Bias Adjustment (no signal present):

1) Connect TP501
2) Adjust RT501 for 7.5mV reading on the VTVM.

...and duplicated for the other channel.

So here's my dumb question: do I just touch the multimeter to the TP501 and the other lead lead of the multimeter to the ground/chassis and adjust the pot to 7.5mV? Does it matter red or black? I'm assuming the unit is powered up, but no speakers or source, correct?

Sorry for the noob question, but these are waters I haven't swam in before. Hey, you gotta start somewhere ;)
 
Bias is a measure of current between two points, generally measured in actuality as voltage between two points, and current is then divined from the voltage reading. The manual should give you two measurement points for each channel. If it doesn't, then you need to know enough about electronics to find your own test points, as the manual has an obvious error in that regard.
 
OK, I think I got it.

I set the multimeter to 2V.

Initial readings showed up as 0.021 or so for L/R. I increased a bit for both channels to get to 0.074 on each. Sound good?

I noticed a bit more hum coming from inside the unit as I increased the bias.
 
you probably - most likely measure between ground and tp501.(test point 501)

with your meter set for dc volts.

there may be a test point pin near tp501 marked ground or gnd.

the chassis should be at ground potential.



you will not fry anything measuring the voltage between tp501 and the chassis - unless it the wierdo circuit from hell)

send me the diagram and I will look at it - but my pc locks up when I try to read private messages.

do not slip up with your meter probes and short any thing out.

If the board is really really packed with components you might want to use some heat shrink to insulate your meter probes - just leave the tip's of your probes un insulated.

let the sony warm up and stabilize for 20 minutes before adjusting it.

It is kinda scary giving any kind of trouble shooting or adjustment advice over the internet.

I would hate to hear that you slipped up and shorted out something.

that is a kool reciever.

wait at least 4 hours if the sony has had a signal from any source playing guns and roses - ha ha

I like all kinds of music - mostly rock

I think there is at least 2 g@r songs I like.

the singer for g@r sounds like he is singing thru his nose most of the time.
 
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Hi Mark,

I think I got it! TP501 has two prongs closely spaced together shooting up from the board about 3/4 inch. I measured between those two prongs. In my first post, I adjusted for an incorrect reading (forgot that mV = 1/1000th of a volt, d'oh). So, I set each channel to read 0.007.

Time for some Axl! :banana:
 
the second pin is probably ground.

did you let the sony sit and warm up for 20 minutes or so before adjusting it ?

I had a lot of fun fixing my akai gx - f71 cassette deck

it had several power supply problems.

I even used a new material from 3m to replace some thrust bearing surfaces in it.

3m sent the stuff to me for free.

I do not know why I fixed it - I have a semi high end cd recorder and 2 pc cd recorder's
and 2 md deck's.

I guess it looked too kool to throw away.
 
Congrats on getting that deck up and running. :yes:

At first I didn't let it warm up but a couple of minutes. I made the adjustments. After thinking about it, I decided to leave it on for 15-20 more minutes and measure again. Everything seemed stable, the right channel increased by 1mV only. So, I think we're good to go.

Did I mention that the sound improved after adjustment? Sure enough, bass was tighter, less 'smearing' of the sound at higher volumes. That could have been distortion creeping in earlier. All I know is that now it sounds mighty fine!
 
Another GX10ES just showed up on the bay. It is using the exact text (maybe not exact, but pretty close) as the on listing mentioned in the OP of this thread, but with horrible pictures.

If I had never seen a receiver from that series I would not bid as the pics make it look like crap. big time. Just a heads up for the original seller. If he even is worried about it.

here is a link
 
Yes, the pictures are indeed horrible. It doesn't take that much effort to get some good pictures providing one has a decent digital camera. It's amazing what it can do for a sale as well.
 
Yes indeed, the Seller has copied excerpts from my original auction and has edited it of which I certainly don't begrudge him because I am certainly guilty of doing the same. Pictures definitely are important on an item like this.
 
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