Ok,
Now that I've got that out of my system in my last post.....I'll go ahead and try to help you out (presuming that you will fill out your profile!), just to show I'm not really a jerk!
asyd7 said:
I just picked up a Sansui QRX8001. It did not seem to be decoding correctly, due to the fact that when switched to VARIOous modes, I would have to compensate heavily with the balance on both front and rear. I took it in to the local high-end/vintage repair shop and they believe that it needs a new chip.
A) It's not a "chip". I've probably got more experience with these receivers
than anyone except the original factory. In over 10 years of dealing with
them I've found exactly ONCE that a decoder IC was bad.....and in that
instance I'm pretty sure it was blown by the owner "messing" with it, rather
than it going bad on its own!
B) The fact that your "local high-end/vintage repair shop" THINKS thats
what the problem is.......reflects poorly on them, both as to their experience
level with the QRX series receivers, and diagnosing the fairly complicated
circuitry found in them!
Of course, they probably just used that as a means of bailing out on the
repair......and pointing you towards something new and cool. In which case,
they could almost be forgiven for at least not sucking you into a massive
repair that they didn't want to do.......and you wouldn't want to pay for!
Questions:
How do I figure out if it is really the chip?
Where/When/How much can I get a chip?
Are there suitable replacements?(from other receivers)?
You really can't without some intense troubleshooting through the circuits.
However if you spend a little time to research previous posts here, you'd see that most likely the source of your problem is the "cold solder pass through joints" on the function select pcb. This IS NOT simple repair, gaining access to the joints and repairing them correctly is very time consuming and difficult.
The ICs are found in all the QRX-*001 series receivers...so you could buy another one. I'm about the only place I know of that "stocks" them, but I don't normally just sell parts as I use them for restorations. And, there's
an extremely high probability that there is nothing wrong with the chip anyway!
Any other info would be great.(QR*500 series vs QRX)
Thanx for all of your help.
You're comparing first generation Sansui decoding against second generation "vario-matrix" IC decoding. A major difference!! Again, do a search here through the back posts and you'll find lots of great info comparing various models and the development of Sansui Vario-matrix decoding!
ps; I'll bet you could have filled out your profile quicker than I could write this post!