Hot Rod Deluxe w/ no sound to speaker only to preamp

[bipton]

I have a Hot Rod Deluxe I am trying to repair and not paying attention I replaced a diode (D18) right above one one of the Omron G6A-274P signal relays, I turned it on for a minute for two and had sound but after that, it does not output any sound. I do get signal from the preamp jack when I plug headphones into though just nothing to the speaker. I replaced the diode again and turned it the right way. Can anyone help shed some light on what I may have ruined please?

Thanks
Jason

[bipton]

Does not anyone have any ideas for me? Is there an irc channel with ultra techies I can join?

[Gravity Jim]

Take it from me... you won't find more knowledgable amp techs anywhere on the web, but show some patience. They'll be along.

[bipton]

When I plug the guitar in and strum it, I can put my multimeter (set to dcv) to the speaker output jack and see the voltage changing, is it possible that the transformer may have something wrong? I measure around 580v @ pin3 on both tubes also and the plate resistor check out ok.

[JAM]

When I plug the guitar in and strum it, I can put my multimeter (set to dcv) to the speaker output jack and see the voltage changing, is it possible that the transformer may have something wrong? I measure around 580v @ pin3 on both tubes also and the plate resistor check out ok.

Are you sure you're measuring correctly? I doubt the plate voltage could be as high as 580vdc. What do you mean by 'plate resistor'? The output tubes dont have plate resistors. Maybe you're referring to the screens.

[bipton]

Yes the screens. I have my multimeter set to dcv @ 1000, I place the black on the chassis and the other probe on pin 3 of the power tubes and both read 580 give or take a few volts.

[Kap'n]

If you don't know what you're measuring, should you be sticking your hands inside something with lethal voltages?

[bipton]

My battery in my multimeter was low The voltage is where it should be, I have checked, dbl checked, and reflowed any suspicious looking points and all of the sockets. I can plug the amp in from the "preamp out" jack to my line 6 and play, it sounds good, but no sound to the speaker still. If I turn the volume all the up I can hear a very faint sound (whatever I'm playing on my guitar) but it is very faint. Is it possible that the output transformer is bad, and is there a way I can test it?

[Mesotech]

I know you've probably already done this, but sometimes it seems to be the simple things. Make sure your speaker is plugged into the proper jack, and not the external jack.

[bipton]

Yeah, I checked that also ;)

[NTBluesGuitar]

Have you tried a different speaker? One that you know works?

Something in the power amp isn't happening...hmm...plate load resistor on the PI come open maybe?

Any solder joints or anything look charred around the screen resistors (R61, R62, R64, R65)?

[FrankJohnson]

My battery in my multimeter was low The voltage is where it should be, I have checked, dbl checked, and reflowed any suspicious looking points and all of the sockets. I can plug the amp in from the "preamp out" jack to my line 6 and play, it sounds good, but no sound to the speaker still. If I turn the volume all the up I can hear a very faint sound (whatever I'm playing on my guitar) but it is very faint. Is it possible that the output transformer is bad, and is there a way I can test it?

Don't mind me.......I am not a tech, but do have one of these and have had many of the problems that have been mentioned on this site.

In case I missed it, I will ask - have you swapped the power tubes with known good tubes?

I had a problem like you mentioned. It also had loose pins where the tube sockets go into the PC board.

[bipton]

I've changed the plate load resistors, along with a few more as mentioned in other forums, yeah I have brand new tubes to swap in/out of it, and I have re-flowed all the solder joints.