Engoodening of Fender Hot Rod Deluxe 1 (possible?)

[crooked_teeth_pete]

Salutations all,
i recently acquired this aged and badly sounding (yeah, surprise surprise) Fender HRD for almost nothing. I never really fiddled with insides of an amp, but i have some experience with soldering, modding and building effect pedals, and i really want to learn ins and outs of amp maitenance and (possibly) building.
Mostly because nearest amp tech in this dump of a country lives like 150km away. Bear with me please.

After i opened this thing, i noticed something like hotglue around the caps. Is that normal? Also, it seems there was some burning damage around bias pot area. Bias was set as low as it could go, i measured 18.8 mV. When turned fully clockwise, it goes up to 53mV. I left it at 45mV, definitely sounds better, but not much. Tubes are some JJ 6l6.

Solutions? How do i uncrap this thing?
I checked out a lot of pages and few possibilities stand out for me.

1. Fromel mod kit
https://fromelelectronics.com/products/hrdx-mods
This seems like simplest solution. Drain the caps, resolder the parts, change the tubes and hope for the best, right?

2. Turn it into 5f6-a Bassman
https://www.mojotone.com/Tweed-Bassman-Style-Small-Parts-Kit
I saw a dude on youtube turn his HRD into a bassman using this kit, he used original chasis and transformers, while rest of the parts came from the kit. Doable for a noob?

3. Turn it into a Dumble
https://luigiretro.com/HRD2ODS_retrofit_pcb
This seems like the biggest undertaking, not only that parts list is huge, i'd also have to order them myself from Mouser or something.

4. Buy a better amp
Nope, i know it would be easier AND cheaper, but i want to learn.


Some pics i took before, if any more are needed, just let me know, i'll snap them later tonight. Thank you for your time, and have a good one.
Pete

[mresistor]

The blue and gray large filter caps are leaking electrolyte and they need replaced asap.  the 5W cement resistors in the burned area of the board need to have one end lifted off the board so there is no more heat damage to the board,,  both ends could be lifted if both resistors are supprted or tied together.  You need to determine if the burned area has any damaged traces or conductive areas.


The Fromel kit is ok if you feel confident enough to install it. Bear in mind the ribbon cables should be handled with extreme care as the wires can break off with too much movement back and forth. you do realize that you'll probably going to have to remove the main pcb in order to get to the solder pads on the backside to remove and replace components, this can be tricky and you don't want to use too much heat when desoldering.


Always take some close up pictures of the power supply leads and where they connect to the board and anything else you take apart just in case you forget where things go. 


If you convert to a Bassman you will lose the reverb. 

[tdvt]

As already pointed out, those big e-caps are already failing.


As someone who is probably not all that much further down the amp-building path & the fact you are looking for a learning experience, I would suggest keeping it stock & just get it working first.


Take advantage of the fact that you know that it once worked in the stock configuration, & that there is reliable documentation easily available, to get you there.

[AlNewman]

Yeah, not only the big electrolytics, but I would suggest replacing all the electrolytics while you're in there.  There probably won't be enough lead on those cement resistors to get them off the board, I would suggest ordering 5W wirewound resistors so you can fly them off the board a bit.  Also the diodes in the bias section can be replaced, (maybe upgraded), also to get them off the board a bit.

The schematic suggests .068 A at the test point for your power tubes, so after replacing the caps if you are still not getting enough current at the cathodes, you may be looking at a new set of tubes.  .068 is still a fairly low bias, but .053 is pretty anemic.

There are a lot of things that can be done to make the amp really good in all channels, but the clean channel is usually pretty good out of the box and makes a great pedal platform. 

Some of those hot rod line amps are better than others in terms of board and ribbon cable quality and are much easier to work on.  Depending on which one you have would be a good indication to how successful doing a bunch of mods would be without damaging something and basically making life miserable.  You'll need a few key things, like good snips, a decent pencil iron, and desoldering braid at the very minimum to do any work at all.  Watch lots of videos and do some homework on the amp before you start. 

[crooked_teeth_pete]

Thank you very much for all the tips and answers, you guys rock! I've decided against converting the amp, might indeed be a bit too much for first timer. I think i'll go for Fromel mod, as it already replaces a lot of faulty caps and rest of the modifications seems pretty similar to pedal work i already did. I will replace rest of electrolytics and 5W resistors as well, as suggested. I found step by step guide for the mod here: https://fromelelectronics.dozuki.com/Guide/Hot+Rod+Deluxe++and+Deville+Mod+Kit+-+April+2022/1#comment-65
I'll source all the parts from Mouser, i'm broke already and ordering the full kit with overseas shipping and taxes would put me straight into poorhouse. Will there be a big difference in quality of parts?

[pdf64]

The HRD info here may be of interest http://hotroddiy.com/