Pioneer SX-939 rebuild

[roccus]

So I got the covers off the 939 and peeking around this looks like a huge can of worms compared to anything I have recapped in the past I am a bit nervous about messing with the tuner section as I have never worked on one. These Pioneers don't solder the wire harness in to the boards instead the coil the wires around posts wonder how the get continuity still after all these years and wonder if I should put a dab of solder on each one of them another thing I note is the pc boards are not silk screened with the usual + to show polarity for the caps so probably will do 1 at a time.. I think my plan of attack on this is to do 1 section at a time then DBT with variac after each section is done to see if I'm still good.

 

[laatsch55]

If the wire wrapping isn't loose or broke, leave it be, it's actually a gas tight seal....don't rely on the service manual or schematic for cap replacement. Put em in like they came out. Many, many revisions of those boards so they could not agree with the paperwork you have...

 

[Billboard]

If the tuner is working, do not touch it! Not many techs are capable of re-aligning the tuner.

 

[orange]

When it's running right, that pile of rainbow spaghetti is a kick ass 80 watts per channel beast that sorta resembles your avatar, pure joy.

 

[roccus]

I started replacing some of the caps this evening very tedious all the leads are bent over flat against the bottom of the board and being 70's pc boards the pads are fragile I will hold off on the tuner board till last but to do the caps on it that string needs to come off the pulley to be able to flip the board... I have my winter bench just about all set up the waopl is up on it now just need to hook up a couple power strips and run my plugs

 

[62vauxhall]

If the tuner is working, do not touch it! Not many techs are capable of re-aligning the tuner.

I would agree with that. It was proposed to me once that just the change of the physical size/mass of components like capacitors could alter the "environment" enough to cause the need for re-alignment.

 

[orange]

No, they just build them differently now. You can build a cap with smaller size and such that does much the same as the vintage ones.

What is worse is when I was at a computer repair/sales shop and an NEC SyncMaster CRT monitor let out a huge POP and smoke and after the cap had gone nova watched as the picture started to roll and scanning fell out of sync until the owner of the shop just calmly yanked the plug.

WOW.

Something much like THIS:

 

[roccus]

Out with the old in with the new... those power caps have started to split and leak on the bottoms

equalizer, mute, and power boards done new power caps in dim bulb power up went very well

Next onto the control board

 

[roccus]

If the tuner is working, do not touch it! Not many techs are capable of re-aligning the tuner.

the carver tech I found said he can realign the tuner so I will do it last... I also am going to rebuild my TX9100 and have him realign that as well

 

[laatsch55]

Good to have a tuner guy close....

 

[roccus]

The old power caps I pulled out...

 

[orange]

the carver tech I found said he can realign the tuner so I will do it last... I also am going to rebuild my TX9100 and have him realign that as well

My 9100 is fine, my 7800 is the one needing alignment. Don't tell your lady Pioneer had better color coordination than she does with all of them wires tho...

 

[orange]

We used to have good techs around town but they were too nice and got run over by people.

 

[roccus]

We used to have good techs around town but they were too nice and got run over by people.

yea good techs are going away in this day of what I call douche bag electronics... use it once and toss it out

 

[orange]

Hey Ray, did you try getting caps that didn't get sent from straight outta CINA?

http://stores.ebay.com/Liberty-Elec...44336018&_sid=640018548&_trksid=p4634.c0.m322

There are other places, I just recall this guy has been around a long time, anything but CINESE packing.

 

[roccus]

Hey Ray, did you try getting caps that didn't get sent from straight outta CINA?

http://stores.ebay.com/Liberty-Elec...44336018&_sid=640018548&_trksid=p4634.c0.m322

There are other places, I just recall this guy has been around a long time, anything but CINESE packing.

No actually I ended up getting the caps out of candada

It is all capped just got to do bias and let it burn in a bit and test functions out...

here is pic from this evening on first power up on DBT... no smoke no sparks no flames

 

[laatsch55]

Nice Ray...

 

[orange]

Don't you mean CANANDA?

 

[roccus]

Don't you mean CANANDA?

No candada! geez you audio file guys! lol