Ashdown ABM 500 Evo III APC058 Schematic

[CosmicCharlie73]

Hi all,

First time poster here!

I'm wondering if anyone here has the schematics for the backboard of the Ashdown ABM 500 Evo III, the APC058?

Specifically I'm trying to find out what the transistor TR6 is. I cant find this specific schematic anywhere, and myself and my amp tech have both emailed Ashdown with no response.

Picture of board attached.

Thanks for any and all help!

[Jazz P Bass]

The schematic set that I have says ACD058.
Not sure if it will help but here is the set.

[The Dude]

Unfortunately, it looks like I have everything EXCEPT the output board. I see the transistor is cracked in your pic, but can you read any numbers on the remaining parts? We may be able to come up with ideas.

[x-pro]

According to the schematic (ABM EVO3 Back PCB Schematic 1.pdf) provided by The Dude, you can safely put a transistor: https://static.chipdip.ru/lib/986/DOC003986665.pdf
It even has the same pin numbering.
If you don't have anything from the list in the datasheet, you can install other transistors, but make sure the pins fit into their holes.
2N5551, 2N3904, BF422, 2N2222

[CosmicCharlie73]

Thanks for everyone's input and help here. It is very much appreciated. I've passed all this onto my tech, and I'll write back with his responses or further questions.

Cheers

[Mick Bailey]

Its most likely the complemantary to TR5. I'm thinking TR6 is a BC459 as they use quite a few of the for general purposes, but let us know what TR5 is.

Its not critical at all in this location and the recommendations by x-pro will work perfectly.

[CosmicCharlie73]

Hey guys,

Dave from Ashdown got back to me and sent me the schematics.

ACD058 was included, but there were two other schematics specifically for APC058. I've attached them for future searches and for you guys to add to your own archives.

Thanks for everyone's help, keen to get this fixed!

Cheers

[Mick Bailey]

My assumption was incorrect So it turns out it's a ZTX614 Darlington. I can now see that from the broken device outline I should have looked closer.

[J M Fahey]

What x-pro suggested.

From what schematic shows. under Fsw control Tr6 enables/disables +15V feed to regulator IC3 , which may be an LM7812/09/05L (measure DC voltage out to confirm) which in due time feeds IC1 which apparently decodes Fsw "signals" and drives whatever function is desired.

So Tr6 job is "easy" , switching only 15V and most probably passing only a few mA, whatever IC1 needs.

*BUT* it is cracked, so it probably suffered a catastrophic shorted load, so please check IC3 health, and worst case IC1

Something overloaded and cracked that poor little transistor, not sure "just replacing" it will be enough.

[x-pro]

I excluded the consideration of a compound transistor because the schematic shows a single element in the package.
Correct, even on schematics, a compound transistor is shown as two elements in one package, or it is specified as “Darl.”

[Mick Bailey]

The schematic is misleading - there's no reason not to show the correct symbol for the device. It's also frustrating that component values aren't shown and you have to reference a parts list.