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SX-1050 Full Rebuild Parts List - Completed Project

I just got one on the bench from a tech. This thing is huge. I need a bigger bench.

I was told one channel is out. It came out of protection on DBT but when I pulled there cover, the tech just pulled the molex connectors to the outputs on there bad channel. Replaced the outputs on the bad channel and it now works. Drivers tested good.

Going to recap it using wyatt's or MTF's BOM. Can't wait to hear it.
 
just a quick follow up. replaced outputs per wyatt's BOM and it came out of protection. recapped power amp, power supply 'A', and protection boards. Cleaned the noisy volume pot.

this is a fantastic receiver.

Thanks everyone for this great thead.
 
soundguy9 said:
Hello Everyone,

My unit was all original and running well until recently. It suddenly popped and got very noisy. I did a rebuild of the two power supply boards and it came back to life. The problem was related to the two 470uF caps. They were completely out of spec.

Then I did a rebuild of the phono section and noticed an improvement in the sound. So I moved to the power amp board. I did the rebuild but I was not able to adjust the DC offset and bias voltage. Did a quick inspection and realized that I had not soldered the Q17/Q19 and Q18/Q20 leads. So I added solder and I was able to adjust the voltages on the board. I turned it off and back on and I am no longer able to adjust the bias and dc offset.

I have been following the schematic, transistor orientation and so far they all check OK.

Some of the voltage readings are completely out of specs and I wanted to share it here and see if you are able to direct me to the problem. I attached my measurements but the collector on Q7 is reading 58V vs -3V! I am moving down the circuit and so far everything is checking out correct.

Any TSing suggestions would be appreciated.
Click to expand...
You should consider creating your own post so it’s not combined with this one.
 
I completed the build on my daily driver SX-1050. It really opened up the sound and I am very happy with the final results.
This unit posed a new challenge as there are no reference designator makings on the PCB. If you are an ameture such as I, you need to take your time and check every component two or three times before swapping out the old with new components. There are many opportunities for error on the power amplifier board.
 
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Hello everyone,

First of all, I would like to thank the author of this thread for the great work and for providing such a complete list of components. It is a very valuable resource for anyone planning to restore a SX-1050.

I recently started working on the restoration of my Pioneer SX-1050. I purchased a complete kit on eBay to replace all the electrolytic capacitors in the unit.

However, I still have some questions regarding the transistors. Is it generally recommended to replace all of them during a restoration, or only specific ones that are known to become problematic with age?

I am also wondering if there are particular transistors that could have an impact on sound quality and might be worth replacing preventively, or if it is better to leave them as they are as long as everything is working properly.

Thanks in advance for your advice and experience.
 
Pef said:
Hello everyone,

First of all, I would like to thank the author of this thread for the great work and for providing such a complete list of components. It is a very valuable resource for anyone planning to restore a SX-1050.

I recently started working on the restoration of my Pioneer SX-1050. I purchased a complete kit on eBay to replace all the electrolytic capacitors in the unit.

However, I still have some questions regarding the transistors. Is it generally recommended to replace all of them during a restoration, or only specific ones that are known to become problematic with age?

I am also wondering if there are particular transistors that could have an impact on sound quality and might be worth replacing preventively, or if it is better to leave them as they are as long as everything is working properly.

Thanks in advance for your advice and experience.
Click to expand...
I generally do not swap up all transistors but I take a look at the Top Ten known bad transistors from this list and compare the service manual to see if there are any that should be swapped.

dlucy

Thread 'Top Ten Worst Transistors - noisy, failure-prone, whatever... and replacements'

I've followed AK advice for several vintage solid state receivers now and the difference in sound, from recapping and from replacing "known-to-be-noisy" small signal transistors to be amazing.

While following along with others' threads and trying to help out with "consider replacing these known-noisy transistors", I've tried to find a "top ten list" or "worst transistors" thread, but found none.

If there is a long-standing "which transistors go bad or go noisy and you should replace when you can" thread, please post a link.

If not, please contribute your "worst, replace ASAP"...
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