Hot Rod Deluxe service points

[Rhodesplyr]

I'm working on a MIM Hot Rod Deluxe (2002 board) and have dealt with the standard problems with the resistors that cook the board, solder joints, B+ caps, jack contacts, and so forth. It's for a musician friend who gigs a lot, so I want it to be as solid as possible for a HRD.

I noticed that the 1,000uF/35V radial caps next to the 470Ω/5W resistors seem to get hotter in operation than I think they should, so I'm going to replace them with higher temp rated parts for a better safety margin.

Are there other common failures in HRDs I should try to fix before they fail?

FWIW, this one has a Ruby spring tank in it that doesn't sound very good -- too "springy." I replaced another HRD tank last month with a new Belton, and it sounded much better. Same vintage HRD. Are they prone to tank failures, too?

[nevetslab]

I'm working on a MIM Hot Rod Deluxe (2002 board) and have dealt with the standard problems with the resistors that cook the board, solder joints, B+ caps, jack contacts, and so forth. It's for a musician friend who gigs a lot, so I want it to be as solid as possible for a HRD.

I noticed that the 1,000uF/35V radial caps next to the 470Ω/5W resistors seem to get hotter in operation than I think they should, so I'm going to replace them with higher temp rated parts for a better safety margin.

Are there other common failures in HRDs I should try to fix before they fail?

FWIW, this one has a Ruby spring tank in it that doesn't sound very good -- too "springy." I replaced another HRD tank last month with a new Belton, and it sounded much better. Same vintage HRD. Are they prone to tank failures, too?

The Input Jacks, as well as the Foot Switch jack (same 4-pin pattern). What Fender is using now has thread that goes all the way up the bushing, instead of part way, which is what you have in that HRD. The nuts over time always seem to loosen and go away, and the plastic thread slowly fails, which ends up causing the solder joint fractures on the jack connections. I haven't yet tracked down the newer parts Fender is using, but it's on my agenda to find.

I've been putting a small cut piece of fishpaper underneath the 470 ohm/5W resistors to reduce the PCB baking those do to the board. Good thought in using the 105 deg C caps there.

Any time I've a HRD series amp on the bench, I'm looking at the tube PCB closely for solder joint fractures, and, when I have to pull the Main PCB off, I'm doing full solder joint inspection everywhere. My avatar shows my inspection tools (surgeon's headlight & loupes). Fender has resorted to making their solder mask pad diameter for the large solder pads used for the power supply 'lytics tiny, which leaves very little space for a good solder joint. I often desolder that, and scrape away the solder mask and then re-solder, after pushing the cap leads back down, so there's proper pad size to solder to.

[Leo_Gnardo]

Are there other common failures in HRDs I should try to fix before they fail?

The plate resistors in the output drive tube circuit sometimes go open circuit at random. No wonder, with tiny 1/4 watt parts. Half watters are plenty good enough in this application.

Screen grid resistors - well some folks like to see them used as fuses. If that's not your view, change 'em out for 3 or 5 watt resistors.

Plastic speaker plug - often becomes intermittent. Substitute a quality Switchcraft 280. While you're at it solder the speaker connections instead of having dodgy push on connectors.

External speaker jack has leaf switches on it to select output impedance. These often go intermittent. If the amp's never going to be used with an external speaker, just wire the 8 ohm OT lead to the output jack & do away with the ext speaker jack.

And of course the notorious dodgy plastic input jack. Put a Switchcraft 12A there and look forward to decades of no further input jack problems. If you use plastic/fiber shoulder washers, tighten the mounting nut extremely well. But if you mount the new jack direct to chassis, best to use a star washer behind it to make good ground contact with the chassis, and you can remove the green "fly lead" ground lead from board to chassis because if you don't there's certain to be a ground loop hum.

[Rhodesplyr]

One tweak I read about was changing the Master Volume pot on this series from a linear to an audio taper pot to make it more user-friendly. I noticed that the MV pot is pretty abrupt on this one.

[mozz]

I think that was the model i relocated those resistors. Bolted 15w finned aluminum ones to the other side of the chassis.