@SamEassa - Start a new thread. I agree there are alternates - I have been looking at using STD-01p and STD01n, or STD-03 . This thread is plenty long to wade through, and it the current design is a core ingredient. (IMO slightly better but not audibly better than using darlingtons.) My 2 cents....
Angelo1960
New Member
Hi, I would like to know where can I buy only the printed circuit board for editing the STK0050?
I am in Italy
I am in Italy
merlynski
Curmudgeon Electronicist
You can download the info from the zip file at the bottom of Post #1 to have them made by any PCB maker that can handle Gerber files, or
Search for STK0050 on ebay and about the second listing will be for a pair of circuit boards and heatsink plates, along with a bill of materials for components from various sources. Cost will end up being between $50 and $100 (US) for parts and materials to build them yourself (including the boards and 'sinks). FYI, buying and selling is not allowed in technical forums. If you become a subscriber member you can access the Barter Town section for buying and selling. Lots of good info in this thread, read the whole thing at least once.
Welcome to AK!
Double check your work.
Check for proper component placement. Lots of images to use as a reference.
Check the solder connections.
Check for no continuity between the big transistors collectors and the heatsink. No continuity!
Use the DBT, Dim Bulb Tester on the first power up, 75 watt bulb should be good.
Turn the trimmers on the modules to full CW before plugging into the DBT. (Edit)
The bulb goes bright at first as the caps charge but should dim down to less than a glow.
If the bulb dims quickly your good, if it stays bright after a moment turn the DBT tester off quickly and look for the short.
If the set has no shorts, the DBT dimmed correctly, then check your channels for DC balance.
If the DC Balance is good, check the Idle trimmers for function per the SM procedure. Then reset the trimmers back to full CW (Edit) before plugging into the wall.
If the set was inop before you started on the module replacement:
Have you check the pre-stages using the resistors?
There's a procedure.
Check for proper component placement. Lots of images to use as a reference.
Check the solder connections.
Check for no continuity between the big transistors collectors and the heatsink. No continuity!
Use the DBT, Dim Bulb Tester on the first power up, 75 watt bulb should be good.
Turn the trimmers on the modules to full CW before plugging into the DBT. (Edit)
The bulb goes bright at first as the caps charge but should dim down to less than a glow.
If the bulb dims quickly your good, if it stays bright after a moment turn the DBT tester off quickly and look for the short.
If the set has no shorts, the DBT dimmed correctly, then check your channels for DC balance.
If the DC Balance is good, check the Idle trimmers for function per the SM procedure. Then reset the trimmers back to full CW (Edit) before plugging into the wall.
If the set was inop before you started on the module replacement:
Have you check the pre-stages using the resistors?
There's a procedure.
Last edited:
Ronie
Member
oh boy....
so i finished both module and installed. everything looked good. power on and blew fuse 4..i didnt get a dim bulb yet, making one right now.
a little bit of history. i bought the sx780 with no sound, no relay click.
after checking turned out one of the stk was bad, so I removed it and it powered on. hooked up speaker and it played fine... on one channel of course... for 3 minutes and blew fuse 4a.. im so dumb.
replaced the fuse and it just blew again.
removed the other pack and it powers on and the relay clicks back on.
so i built the two replacements for the stk and installed it but the same thing is happening.
sooo. whats next? i got one new stk from ebay but who knows if it works.
i read here about shorting pins 1,3,8 and 0 to see if the rest of the circuit balances out? can i do the test with both stk's removed?
is there something i can check before that?
also, i do get continuity on transistor q1 after wiring it to the board, on both modules.
so i finished both module and installed. everything looked good. power on and blew fuse 4..i didnt get a dim bulb yet, making one right now.
a little bit of history. i bought the sx780 with no sound, no relay click.
after checking turned out one of the stk was bad, so I removed it and it powered on. hooked up speaker and it played fine... on one channel of course... for 3 minutes and blew fuse 4a.. im so dumb.
replaced the fuse and it just blew again.
removed the other pack and it powers on and the relay clicks back on.
so i built the two replacements for the stk and installed it but the same thing is happening.
sooo. whats next? i got one new stk from ebay but who knows if it works.
i read here about shorting pins 1,3,8 and 0 to see if the rest of the circuit balances out? can i do the test with both stk's removed?
is there something i can check before that?
also, i do get continuity on transistor q1 after wiring it to the board, on both modules.
Ronie
Member
i typed this before i saw your reply..
update..
removed one power pack (the left side - if the receiver is upside- looking from the front) and put new use and it powers on and relay clicks. no blown fuse.
thanks for the help guys, i truly appreciate. this project is way more than i have done before but with a little help from you guys i think i can get it done.
thanks again.
update..
removed one power pack (the left side - if the receiver is upside- looking from the front) and put new use and it powers on and relay clicks. no blown fuse.
thanks for the help guys, i truly appreciate. this project is way more than i have done before but with a little help from you guys i think i can get it done.
thanks again.
petehall347
the brandy coffee man
continuity to where ?
Ronie
Member
continuity against the chassis or on the heat sink the board is mounted on, but only if the sink is connected to the chassis.
i put in the stk from ebay and it powers on, relay clicks and no blown fuse.
i took measurements from both power packs and q19, q20, q25.
should i start another thread or post it here?
i put in the stk from ebay and it powers on, relay clicks and no blown fuse.
i took measurements from both power packs and q19, q20, q25.
should i start another thread or post it here?
petehall347
the brandy coffee man
looks to me like you have to be looking at the power supply .. it is however strange behaviour from reading no apparent short modules removed . i still think you need to verify the supply first in any case .
petehall347
the brandy coffee man
just to get this right i take it you are measuring continuity from collectors of the big transistors to the mounting plate ?
I'm not sure I like those sil-pads.
Iv'e used them plenty but you have to keep a very clean bench. The razor thin pad is susceptible to contamination and will cause shorts between the transistor and heatsink.
Some of the guys mention not tightening the hold down screw to tight.
On that note: Check your hardware stack-up for proper assembly.
Iv'e used them plenty but you have to keep a very clean bench. The razor thin pad is susceptible to contamination and will cause shorts between the transistor and heatsink.
Some of the guys mention not tightening the hold down screw to tight.
On that note: Check your hardware stack-up for proper assembly.
