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Pioneer SX-1250 recap and restoration thread!

That looks absolutely stunning !

I think it's about time Matt thought about losing that "Junior" tag :yes:

He does pretty "Senior" looking work as far as I can see :yes:

Nice thorough job and great photography :thmbsp:
 
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StereoX said:
Mattsd- I am on the lookout for a SX-1250 for sure! The innards kind of look like a SPEC 2. Fantastic restore job. Are you an EE or formally trained in electronics?
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No, I have no formal training of any kind, most of what I've learned was from markthefixer or research.

Thank you Hyperion, I really appreciate that.
 
mattsd said:
No, I have no formal training of any kind, most of what I've learned was from markthefixer or research.

Thank you Hyperion, I really appreciate that.
Click to expand...

The guy is a prodigy if you ask me. I got to talk to Matt for a short while when he picked up the SX-1250 (it was my old one that you see restored) and I was in awe that someone so young (no offense meant, Matt) knew his craft so well. I'd have no reservations at all about letting him do work for me and may soon ask him to do so. Hint, hint;)

...R1
 
Wow... that is amazing. When I pop open a receiver, I get intimidated by that nest of wires and cords and what not. I suppose it's partly because I lack the full cadre of tools to appropriately dismantle and fix things. That said, I do believe if I put my mind to it, I could probably do it. Inspirational, for sure.
 
I'm new to AudioKarma and late to this thread but I wanted to say "WELL DONE" on the restoration of the receiver. True craftsmenship and well documented as well. Obviously a labor of love. Congrats on your good work. Impressive, very impressive.

Mark B...
 
Matt, I'm about to put my 1250 back together in the next week or so, everything has been replaced including new outputs, I did this about two years ago with Mark's help. After reassembling and before bringing it up slowly on DBT, how should I adjust the trimpots on this they are all new too....It's been sitting in my shop staring at me for 2 years, I think it's time to unleash the beast.
 
Same way you would adjust the originals. Before powering it up, you adjust the bias pots all the way CCW and center the offset pot, what I did to do that is turned it all the way CCW, then depending on the pot, is it a 12 turn or a 25 turn? If it's a 12 turn, turn it CW 6 turns, if it's a 25 turn, 12 1/2 turns CW, it will get it close enough until you do the final adjustment. Be aware that it doesn't hit a stop, it just will make a small click to indicate it's as far CCW as it can go. Then after you power it up (Don't make the adjustments on a DBT!) you can make the adjustments. You will need a screwdriver that has had the shaft fully insulated to adjust the offset pot.
 
great job

Matt, how do you find the ADCOM's so far?
what was the reason you've chosen them anyway?
 
Matt I been a little worried about you up there in Ohio with the weather and all.
Everything OK up your way?
 
omri617 said:
Matt, how do you find the ADCOM's so far?
what was the reason you've chosen them anyway?
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Great, I have had no trouble with them and and the sound keeps getting better and better. I chose them because they were proven replacement for the originals and they were the only ones I could find that were reasonably priced and still had screw terminals, I didn't see those UCC's at Newark until tsd71 pointed them out. I also installed 2.2uF bypass caps across them as well.

Edit: I see that the UCC's are out of stock now. Darn.

Noodle said:
Matt I been a little worried about you up there in Ohio with the weather and all.
Everything OK up your way?
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I'm fine up here, it was a little hairy there for awhile, but in the end it was just heavy rain (I couldn't see farther then about 50 feet at the worst of it and it turned the streets in front of the house to literal rivers in about 3 minutes!), wind and some extreme lightning, I had to shut down the SX-1250 that was running at the time, it got that bad, and I have it plugged into a good surge protector too.
 
mattsd said:
Great, I have had no trouble with them and and the sound keeps getting better and better. I chose them because they were proven replacement for the originals and they were the only ones I could find that were reasonably priced and still had screw terminals, I didn't see those UCC's at Newark until tsd71 pointed them out. I also installed 2.2uF bypass caps across them as well.

Edit: I see that the UCC's are out of stock now. Darn.

Yeah, I was just gonna buy 4 more for my 1250, there were 45 left last week, I think someone bought all of them...it was a steal at the time...they will probably show up on Ebay soon.:tears::tears:
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Matt, great job on the restoration and documentation.

One question, how did you manage to get the chassis so clean?
 
tsd71 said:
mattsd said:
Great, I have had no trouble with them and and the sound keeps getting better and better. I chose them because they were proven replacement for the originals and they were the only ones I could find that were reasonably priced and still had screw terminals, I didn't see those UCC's at Newark until tsd71 pointed them out. I also installed 2.2uF bypass caps across them as well.

Edit: I see that the UCC's are out of stock now. Darn.
Click to expand...

Yeah, I was just gonna buy 4 more for my 1250, there were 45 left last week, I think someone bought all of them...it was a steal at the time...they will probably show up on Ebay soon.:tears::tears:
Click to expand...

I wanted to buy some more of those UCC 36DA at Newark for some of my receivers but I keep finding that I will have to buy MINIMUM QUANTITY in order to get what I need. Fortunately, I got my SX1010, SX1250 and one of my Marantz main caps before they put such a restriction.
 
native said:
Matt, great job on the restoration and documentation.

One question, how did you manage to get the chassis so clean?
Click to expand...

A rag and a Magic Eraser, that's all I used. There was very little grime on it, it was mostly loose dust and I think the dust acted as sort of a protecting layer, so the chassis once cleaned was like new.
 
Great Job!

Well Matt, I am definitly hooked. After making mods to two of my three Sherwoods, I broke down and purchased an SX-1250. Now to order some parts . .
Thanks for the great pics and advise! Regards.
 
Gain matching transistors

I forgot to ask, in the parts list, it is mentioned that certain transistors need to be gain matched. What is the best way to do this? Is a multi meter good enough? Thanks. Looking forward to doing a recap of my 1250!
 
Power Amp Board Transistors

Hi Gang,
I noticed that the parts list for the Power Amp Board (AWH-048A) only shows replacements for transistors Q1 and Q2. While I have these out, I would like to replace all the transistors and diodes. Does anyone have a parts list of recommended replaces for the other transistors and the diodes?
Thanks team,
Jerry
 
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