This will probably come off as a really stupid question (so i apologize for wasting anyones time in advance ) but im very new to the world of amps here and a buddy of mine gave me a 1998 Fender Roc Pro 1000 head and there seems to be something wrong with it. the symptoms are like this, the only think wrong is that you you have to turn the volume up all the way in order to hear even the slightest thing. everything powers up no problem. i took it to a local music shop here and had it checked out by someone i thought was somewhat educated in this field, and he told me that its probably not getting enough power and it would probably cost me close to $150 to get it fixed. so i figured i would come to you guys first (since you guys look like you know everything there is to know about amps ). so i did some research and determined it could be a bad power transformer. swapping that out looks like no problem but finding a replacement for it i havent yet been able to. any other suggestions? or anything else i might want to check before replacing the transformer? any advise would be appreciated. thanks in advance!
oh by the way i hope im in the right forum
oh by the way i hope im in the right forum
Found it, in case we might need it.
http://www.fender.com/support/amp_schematics/pdfs/Roc_Pro_1000_Schematic_B12.pdf
/Hugo
http://www.fender.com/support/amp_schematics/pdfs/Roc_Pro_1000_Schematic_B12.pdf
/Hugo
Ok, assuming you connected everything as it should be; input signal present, you fiddled with all buttons and switches and you still have no sound, take out the fuse XF1 and measure if it’s broken.
A word of warning: Don’t trust the mains switch and pull out the mains before taking out the fuse.
The second check needs mains voltage so be careful.
Check the voltage on TP23, TP24, TP26 and TP27 with respect to ground, which is CP4.
Let us know what you found.
/Hugo
A word of warning: Don’t trust the mains switch and pull out the mains before taking out the fuse.
The second check needs mains voltage so be careful.
Check the voltage on TP23, TP24, TP26 and TP27 with respect to ground, which is CP4.
Let us know what you found.
/Hugo
Fractured solder is the prime enemy in these amplifiers. Get out the high magnafication and start looking. The power supply caps, any power resistors, power transistors and, pots and jacks. The thermal and mechanical considerations on amplifier of this ilk are poor at best.
The jacks that fender uses in these amps are also highly suspect. The pins are quite thin and shear off. Any jacks that are normalled through, like FX send/return, may have oxidized contacts. Try running a a cable between these jacks.
Good luck to you!
The jacks that fender uses in these amps are also highly suspect. The pins are quite thin and shear off. Any jacks that are normalled through, like FX send/return, may have oxidized contacts. Try running a a cable between these jacks.
Good luck to you!
well heres the story behind it, my freind had kept it in his closet for a couple years barely ever using it. he told me about this amp he had sitting around and asked me if i wanted it. before he gave it to me he had tested it to make sure everything was ok and it worked fine he said. when he brought it to my house last week, we hooked everything up and he was puzzled when we couldnt get any sound. just a faint sound coming out. i asked him if he had ever dropped it on accident but he said no. he just put it in his car, and drove it over ( no oopsies ) its been in his closet collecting dust. i dont get it
It takes some practice to recognise bad solderings. From the layout on the schematic I think you need to take the PCB out. This is probably going to be a though job if you are not used to it. I’m just guessing of course.
In case you want to proceed, the big resistors, the jack contacts and pots are, from my experience with other amps, the most vulnerable to broken joints.
/Hugo
In case you want to proceed, the big resistors, the jack contacts and pots are, from my experience with other amps, the most vulnerable to broken joints.
/Hugo
i think so... whats the difference?? 
the tube is glowing to the best of my knowledge. there isnt different intensities that it may glow at, is there? so basically if i start probing at different things and wiggling them around would that be able to indicated whether or not the soldering is bad?
the tube is glowing to the best of my knowledge. there isnt different intensities that it may glow at, is there? so basically if i start probing at different things and wiggling them around would that be able to indicated whether or not the soldering is bad?
Here you see the difference between mono and stereo jacks:
http://www.oselectronics.com/ose_p107.htm
Sorry for the commercial link but the pictures are clear. (Top left)
Wiring inside stereo jacks is different than in mono and often cause problems in instrument amplifiers.
If the tube glows , at least the filament voltage is OK. (12AX7, divided in two halves, top of schematic)
Gently tapping the PCB is a known technique to find bad contacts.
The handle of a small isolated screwdriver does the job.
You could try and measure a bunch of other DC values, many of them have test points (TP) but they should read VDC or just plain -16 or +40 or similar.
No use to measure VAC at the moment.
Is the solderside of the PCB visible?
/Hugo
http://www.oselectronics.com/ose_p107.htm
Sorry for the commercial link but the pictures are clear. (Top left)
Wiring inside stereo jacks is different than in mono and often cause problems in instrument amplifiers.
If the tube glows , at least the filament voltage is OK. (12AX7, divided in two halves, top of schematic)
Gently tapping the PCB is a known technique to find bad contacts.
The handle of a small isolated screwdriver does the job.
You could try and measure a bunch of other DC values, many of them have test points (TP) but they should read VDC or just plain -16 or +40 or similar.
No use to measure VAC at the moment.
Is the solderside of the PCB visible?
/Hugo
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