Yet another SX-1050 recap/restoration. What am I forgetting?

Found it. Upon further inspection the base of Q8 did not have good connection; no solder actually. after a quick touch up, back in business.

EQ board is next.
 
zebulon1 said:
I buy from this seller. You can contact him through the messaging system and ask for a discount. Mostly Free shipping. I usually get four at a time. He will invoice through Paypal. Note: The listing is for two caps.
Ask for the black tops. The main body is blue but I like the black inserts in the top. The other option is white :)yuck:).

Direct OEM replacement in size but they are screw terminal and (10-32 machine screw size) requires a little larger opening in the ring terminals and ground buss on the set.

Adcom 22000uF 100 Volt
No affiliation.

If the caps are not leaking they are probably good. In the SX-1050 the big filter caps really don't get the workout like they would in a higher watt set in which they are also used.
Pretty blue color and bragging rights usually win out! :D

attachment.php
Click to expand...

zebulon1 said:
Fit and finish. Easy install.
Anyone would be hard pressed to hear any difference in sound from one over the other. I don't buy into the dynamics conversation. Not insinuating you were asking but I feel it coming on.
Click to expand...
I have also purchased from that guy...He will give you a deal for the "4". You are correct....Perfect Fit!!!
 
another update

partially recapped the power amp. no issues there.

worked on the filter board since i noticed everytime i push the buttons, either the left or right channel goes out. so i recapped and replaced the trans on that board. onto the push button switches as i try to deoxit. i removed the cover and as i try to put it back together, the switch is now not smooth at all.

is there a technique in putting the push button switches back together?
 
In the power amp, the "awh-047 c1" cap from Mouser, 667-ECQ-V1H684JL
or substitute 667-ecq-v1104jm are both obsolete. One recommendation is to use WIMA 505-MKS2.68/50/10. Is this an OK suggestion? ecq-v1104jm are available from digikey but I'd rather not order just one cap. Also, with the 8 TO3 transistors in the power amp, is it recommended to use an insulator eg mica or silicon? Or just use heatsink grease?
 
Thought I would add that I just finished an SX-1050 and found Q5 in the power supply gets incredibly hot. I then remembered that my last SX-1050 rebuild did the same thing. This is the pass transistor for the -60v supply. The +60v transistor has supplemental heatsinking but the negative does not. Temperatures were in excess of 100C on the body of the transistor. I added a cheap clip-on TO-220 heat sink and temperatures dropped to 65C, more or less the same as the rest of the power semiconductors on that board. Might be a good idea.
 
Take it apart again. There's two tracks and the fingers that ride on them can bend over and jam up. The use of a magnifier hood is recommended no matter what age you are....
 
^ I was able to fix it a bit. still not smooth but functioning properly.

Just finished the tone control board. man that was a lot of work with all those caps. But burn in process in progress. Sounds great so far. I had to adjust the bias after this since it was tripping the protection circuit.

Next is the flat amp board that I'll do sometime this weekend. I hope.

R
 
Last edited:
eentegra said:
^ I was able to fix it a bit. still not smooth but functioning properly.

Just finished the tone control board. man that was a lot of work with all those caps. But burn in process in progress. Sounds great so far. I had to adjust the bias after this since it was tripping the protection circuit.

Next is the flat amp board that I'll do sometime this weekend. I hope.

R
Click to expand...
If you need a switch let me know....Have a SX-1050 parts unit.

Are you going to replace the Main Caps?
 
^^^ DM sent

main caps are still factory and still doing fine. still debating on whether the sound will improve much with switching to 100v caps.
 
DRecovery said:
Thought I would add that I just finished an SX-1050 and found Q5 in the power supply gets incredibly hot. I then remembered that my last SX-1050 rebuild did the same thing. This is the pass transistor for the -60v supply. The +60v transistor has supplemental heatsinking but the negative does not. Temperatures were in excess of 100C on the body of the transistor. I added a cheap clip-on TO-220 heat sink and temperatures dropped to 65C, more or less the same as the rest of the power semiconductors on that board. Might be a good idea.
Click to expand...

I recapped/restored both a 1050 and 1080 a few years ago and did add heatsinking to the PS transistors, as in the pic. This is the 1080 but the 1050 is pretty similar. This is essentially a must, IMO.
 

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UPDATE:

Flat amp done. I also finished off the other 6 trans in teh EQ board. I must say i am very happy with the restoration project. i will enjoy it now. thanks for all of the help/guidance.

here's to hunting down another 1050 or a 1250/1980.
 
tsd71 said:
SX-1050 #1: asr-20 protect relay pcb mount 24 v 653-MY4-02-DC24 (pcb mount pins)
SX-1050 #2: asr-015 soft start relay chassis mounted 653-LY1F-DC48 (solder tabs)

652-3386H-1-501LF for VR3/VR4
652-3296P-1-202LF for VR1/VR2
Click to expand...

CAUTION...

I followed this post and bought the wrong protection relay.
ASR-20 is correct per the SM, but the relay that I pulled from the protection CCA is clearly labeled 48VDC not 24VDC.

The one I will be ordering is Mouser 653-MY4-02-DC48.
Based on the coil resistance, the rail voltage, and the series resistor, there will be about 50v on the coil.
 
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