65 twin reverb issues fuses, etc

[CKuzGuitars]

I have a 65 reissue twin reverb amp. It had some bad tubes and bad solder joints. I am having an issue now where the pcb board has an internal fuse that says it should be 10a 250v. According to what I see in the service manuals there is no internal fuse in the us models and somewhere around a 5a in the export models. Any suggestions? Anyone an expert on this amp that cn help me out? Thanks in advance.

Chuck

[soundguruman]

I think the 10A internal is the filament fuse. If it's blown, the filament could be shorted to something, , internally inside a tube.
although, on the 1990 schematic the fuse is not shown.

At some point manufacturers started fusing the filament lines, although you need a really slo blow fuse, the ordinary slo blow does not really work so well.

[Enzo]

DOn't need an expert, just need a schematic to cover your revision level. Revision F was the first to include the 10A slow fuse. That was 2002.


What help do you need? You have a board with a 10A fuse printed on it. Install a 10A slow fuse. If it blows, look for the problem. Most likely a short in a power tube or a short across the pilot lamp socket.

[Enzo]

DOn't need an expert, just need a schematic to cover your revision level. Revision F was the first to include the 10A slow fuse. That was 2002.


What help do you need? You have a board with a 10A fuse printed on it. Install a 10A slow fuse. If it blows, look for the problem. Most likely a short in a power tube or a short across the pilot lamp socket.

[CKuzGuitars]

I just wanted to be sure that this wasn't an export board. I couldn't find any reference to an internal fuse on any us reissue twin. So, I'll need to order some 10a 250v fuses. The local radio shack only has 10a 125v.

[soundguruman]

I have a 65 reissue twin reverb amp. It had some bad tubes and bad solder joints. I am having an issue now where the pcb board has an internal fuse that says it should be 10a 250v. According to what I see in the service manuals there is no internal fuse in the us models and somewhere around a 5a in the export models. Any suggestions? Anyone an expert on this amp that cn help me out? Thanks in advance.

Chuck

Something like MDL 10A has the right time delay I think, it needs to be extra long, there's a surge when the amp first turns on.
http://www.cooperindustries.com/cont..._MDL_MDL-V.pdf

[Enzo]

The circuit is 6 volts. It doesn;t matter 125v or 250v. What does matter is that it is a slow blow type. Also called time delay, it says T10A on the schematic, T for time delay. Isn't there a T next to the 10A on your circuit board?

I could be wrong, but I think it is a 20mm size fuse, not the 1-1/4" size.

Here is the service manual. There are multiple revisions of schematics. Scroll down to page 14 for revision F. Parts list does not cover all revisions, so rely on the schematic and layout.

[CKuzGuitars]

Enzo, yes it says t10a 250v and it is 5x20mm. Thanks.