Stinky Hot Rod Deluxe

[Kekke466]

Hello fellow technicians,

I've done a stupid thing leaving crocodileclips (when discharging them) over a filter cap when turning the amp on.
To be more precise it was over C33. Now after a while smoke came out from underneath.

I thought nothing happened but the amp keeps stinking so bad. It's like my room is being repainted everyday.
I checked on the output and noticed that the values where quite messed up I meassured 10V over some standard values in the schematic.

Now I know from electronics when you shortcircuit a transformer that the coils burn up from the inside and I think that might be happening?

Today I just couldn't take the smell anymore and I took it apart again.
I found out that the smell seems to come from the choke...

Does anybody have any idea what could be wrong? I hope this isn't going to cost me a new output transformer of 100$ or more?
Could it be if I just replaced the stinky choke everything would be fixed?



I already thank you for your replies to my problem cause I'm desperate to fix this.

[Steve Conner]

I've overheated transformers a few times, and I know that horrible paint smell you mean. It means that you've cooked up the varnish and insulation inside the transformer. It'll stink forever, and it's probably unsafe to use: the insulation is damaged, so shorted turns could develop later.

Does C33 come before or after the choke in the circuit? I don't have the HRDx schematics handy.

If after, then you've probably burnt the choke. Replace it. If you're in Europe, Fender original parts can be hard to get. TAD in Germany carry a fine range of replacements though. If your amp carries on stinking, then you've probably burnt the transformer too, see below.

If before, then you've burnt the power transformer. Replace it, again TAD is probably your best bet for Europe.

[Kekke466]

I'm not sure if it comes before or after. I'm really not a specialist in this.
Also it seems there are 3 sort of transformers in it?

I see one that has many distributions, the filter choke, and another one that's quite big and has 2 black wires, 2 green, 2 black, 1 red and one brown running out. But I can't figure it out from the schematics where is the choke. They talk about T1 and T2. I'm really confused over this.

I uploaded the schematic parts where the shortcircuit took place and where I think is the problem. But what transformer is it that I need to replace now.

This is where I did the shortcircuit...



Primary wiring schematics:
I have the model for 230V/50Hz HRDX.



It's not going to be easy getting a replacement choke since I checked with TAD and they didn't have the model for the HRDX. I live in Belgium so getting anything related to fender is difficult.


Thanks for your help!!!

[Steve Conner]

OK, C33 is after the choke (L1) so the choke is probably what you've burnt out.

I imagine you could use a Hammond choke or whatever, it probably isn't crucial to get an exact replacement. Maybe an American member like Enzo could tell us what the inductance and current rating is: the schematic only shows a Fender part number.

As a test, you could replace it with a resistor: 220 ohm, 5 watt should do. The amp might not work as well, but if it stops smelling, we know we found the offending component.

[Kekke466]

Hi Steve,

I'm going to try that out now. Thanks so much for helping out I thought it was going to cost me a new transformer. I just took out the choke and it smells horrible indeed. I think I'm very sure that this is the culprit!

I can't believe this little thing can stink so bad even when it's not turned on.

[Kekke466]

Just to finish this thread, since I live in Belgium and it might be a hard time getting fender parts. There is a online shop in Holland called tonefactory that can get most of the parts in no time