BIG NEWS!!!!
i found what is wrong. Basically i got tired of it and started swapping transistors from channel to channel. And i found that AC180 is broken. It has a slightly different measurements then the working one and when i swapped it channel started working.
Now only two questions. Where can i get the replacement at a decent price and should I replace both ac180 and ac181 since they are a pair.
i found what is wrong. Basically i got tired of it and started swapping transistors from channel to channel. And i found that AC180 is broken. It has a slightly different measurements then the working one and when i swapped it channel started working.
Now only two questions. Where can i get the replacement at a decent price and should I replace both ac180 and ac181 since they are a pair.
Just swap the one transistor.
Don't forget that you could substitute AC128 for it ( and AC127 for the other)
( you may have to use a clip to attach them to the heatsink)
You will not find a matched pair and they were probably not matched in the first place.
Well done.
Andy
Don't forget that you could substitute AC128 for it ( and AC127 for the other)
( you may have to use a clip to attach them to the heatsink)
You will not find a matched pair and they were probably not matched in the first place.
Well done.
Andy
Last edited:
Where do i look for them. I found one locally for like 1 buck used. But where else to look for them?
I contacted a guy he also has ac128 and 127 all for low prices i will probably get all 3 of them just to have spares
Check the speaker output for a short circuit.
127/128 can get hot in summer when used for a long time at maximum volume.🙁
127/128 can get hot in summer when used for a long time at maximum volume.🙁
Yes I will definitely check all the connectors and original speakers and wires for short circuit. Because I suspect that this was caused by someone shorting out the output.
I checked the wires and speakers. And everything is fine. Speakers together with the wire measure 6 ohms DC resistance and work just fine.
Also these capacitors that I didn't know the name of are apparently polystyrene capacitors. Everyone says that they don't need to be replaced but i accidentally broke one of the legs of on one of them... Woops now what do i replace it with. Can i just use some film capacitor like WIMA or something.
Hello i just wanted to say thank you for helping me. I replaced both output transistors on the broken channel. I was lucky that a local guy had a pair for low price...
Thanks.
Thanks.
Guy that sold me the transistors gave me the thermistor too (probably the one that was in the amplifier that they came out of) It was just a regular thermistor. A black plate sandwiched between two metal plates with leads.
Oh no i am really pissed right now.
So i had a accident... Long story short i accidentally made a short circuit on pcb while i was testing repaired amp and i blew up iskra bc254... I confirmed it by swapping the transistors between the channels and fault followed the transistor. I got a new NOS replacements from eBay but they are not iskra and look different. I tried them and amp still does not work.
This was a stupid mistake and i am REALLY PISSED OFF...
What should I do now. I can't find iskra replacement anywhere.
So i had a accident... Long story short i accidentally made a short circuit on pcb while i was testing repaired amp and i blew up iskra bc254... I confirmed it by swapping the transistors between the channels and fault followed the transistor. I got a new NOS replacements from eBay but they are not iskra and look different. I tried them and amp still does not work.
This was a stupid mistake and i am REALLY PISSED OFF...
What should I do now. I can't find iskra replacement anywhere.
Transistor Universal . NPN silicon planar-epitaxial transistor for general purposes. ECB
Any, but it happens BCE. Iskra R.I.P🙁
Any, but it happens BCE. Iskra R.I.P🙁
Is it maybe possible that i got a faulty batch from eBay. Listing says "new old stock not tested"
Start by checking all transistors.
Almost any n-p-n will work for you (bc254). There are different pinouts.
Almost any n-p-n will work for you (bc254). There are different pinouts.
But I still don't get why bc254 from eBay is not working in my circuit. Only difference i can see is that original transistor is in To39 (metal can) package and new replacements from eBay are in to92 .
What am i missing? Shouldn't any bc254 be the same ? I was thinking that iskra just put it in a different package and basically copied the transistor design??
What am i missing? Shouldn't any bc254 be the same ? I was thinking that iskra just put it in a different package and basically copied the transistor design??