Any photos of HRDv board connections?

[bassman51]

My amp had developed a loud hum when both drive (not more drive) and the effects loop were used. I discovered loose solder joints in two of the caps near the middle of the board were the problem.

After I corrected the problem some of the labels came off of the wires that I needed to remove. I think I got them on right, and the amp seems to be working fine now, but even after checking the schematic from Fender's sight I am not sure.

There is a fairly large resistor at the upper left hand corner, right under the foot switch that is very hot to the touch. In case that indicates a problem, I hesitate to use the amp for very long.

P15, P16, and P17 are in question. Two brown wires, and one brown with a white stripe. Any help would be appreciated. I had hoped to find some graphic illustrations, but maybe someone here can advise me.

Dan

[steve25]

If the amp is working and not blowing fuses, you got it right, and yes those big box type resistors get hot.
Always draw out of picture of a board when you pull wires off of it!

[Offshore Angler]

If the amp is working and not blowing fuses, you got it right, and yes those big box type resistors get hot.
Always draw out of picture of a board when you pull wires off of it!

Or just take a few pictures. I had to replace the control module in our oven, the digital cameral saved me.

[bassman51]

Or just take a few pictures. I had to replace the control module in our oven, the digital cameral saved me.

Great suggestion!

At first I thought I could get the board out without disconnecting anything, then I thought only a few wires. Didn't stop to think about pictures.

Anyway, something happened while I was studying it last night. The drive and more drive function just quit. The foot switch light barely and momentarily came on. The panel switch does nothing, like its getting no juice.

I am thinking that I may have loosened something while plugging and unplugging the wires, as they connect very tightly.

Anyone have a similar situation?

Dan

[steve25]

Go to the Fender home page and down load a schematic and layout to check how you re-connected the wires as it sounds like you are shorting out a low voltage supply indicated by that low brightness foot swicth LED.

[bassman51]

Go to the Fender home page and down load a schematic and layout to check how you re-connected the wires as it sounds like you are shorting out a low voltage supply indicated by that low brightness foot switch LED.

That was the first thing I did. The pictorial layout did not show the wires connected, and the schematic was confusing to me. The schematic does not identify the light brown transformer wire with the yellow stripe. It only shows 2 brown wires from the transformer to cp15 and cp17. Since there is no indication of polarity, I am guessing that either brown wire is okay.

On another place on the schematic it shows 2 brown wires coming from another transformer location to cp15 and cp16.

Now I am not sure if the problem I have now of no overdrive is related to these connections, or my poking around in ignorance. I was told to check the voltage on the hot resistor with a voltmeter last night. First not realizing to set my pocket meter to AC and getting strange readings, I tried another meter which I had recently received. I think I had is set right, but it arced across the resistor wires. I don't know if that blew something because it wasn't until later that I noticed the loss of the drive channel.

[bassman51]

A tv repair friend looked at the schematic and suggested I check 4 diodes. It turned out that CR24 and CR26 were blown.

I barely made it to the parts shop before closing on a Saturday, but that did the job of getting the channel switching back.

The connections were okay all along. My concern over the hot resistor lead to me blowing out the 2 diodes I think.

Dan

[steve25]

Voltage readings on schematics in reagrds to DC are always taken with the meter grounded, never across a resistor.