Looking at the print, you can see if the distortion is being created by HB1 by swapping where C9 and C10 get their signal, that matches this board. Do you have signal gen and scope, or at least scope (can get signal gen for pc).
I'd say that the problem will stay with the channel. If gates were shorted, would have taken a current path somewhere to cook R10 and R11, and that would be on HB3.
Did RF just give you the print for just the parent board or did they include the daughter boards as well. If so, I could use those as I did find the Rev. B here.
I'd say that the problem will stay with the channel. If gates were shorted, would have taken a current path somewhere to cook R10 and R11, and that would be on HB3.
Did RF just give you the print for just the parent board or did they include the daughter boards as well. If so, I could use those as I did find the Rev. B here.
Ill look into that. I dont have a scope yet but I know an old electronics guru here in town that I can pick up a tektronix from for a good price.
I talked to Steve at RF. He said the only schematics they had for this amp is the Rev B. I did not ask for the daughter board schematics.
Thanks for the insight.
I talked to Steve at RF. He said the only schematics they had for this amp is the Rev B. I did not ask for the daughter board schematics.
Thanks for the insight.
A scope makes troubleshooting distorted signals much easier. When you get the scope, post a photo of the distorted waveform with a 5-100Hz waveform. Remember to post the settings on the scope.
If you're not sure how to use the scope, read page 73 of the car audio site (link in sig line below). Pay special attention to the section labeled 'Best Initial Settings'.
If you're not sure how to use the scope, read page 73 of the car audio site (link in sig line below). Pay special attention to the section labeled 'Best Initial Settings'.
Ok. I will be paying my friend a visit soon. I'm sure he will have a few pointers on how to use it as well. I will go over that section again for a refresher.
I think he said its a 2245 that he has for me but not positive. I love getting new (to me) tools! And theres always another tool you just gotta have!
I think he said its a 2245 that he has for me but not positive. I love getting new (to me) tools! And theres always another tool you just gotta have!
Does anyone have a schematic for the vertical boards in this amp? Specifically the HB3 or HB-POM board?
Thanks for the schematics. Now I need to pick your brain. Pin 14 of the HB-POM for the left (distorted) channel is showing me ~2.04v with black probe on rca shield. On the good channel I am seeing ~10v on pin 14. So my question is, do you know how the numbering system on the schematic relates to the board? Or do you have a picture of one where they have been labeled?
Generally, looking at the side with the components, pin 1 is the far left terminal. You can confirm by reading the resistance from the output (bridging) terminal to pin 16. It should read 0 ohms.
If you have a scope, post a photo of the waveform on the distorted channel (50-100Hz sine wave and loaded channel, preferred).
If you have a scope, post a photo of the waveform on the distorted channel (50-100Hz sine wave and loaded channel, preferred).
I'm sorry I meant the number designation for the components on the board.
I still haven't got a scope, hopefully next pay day I can pick one up.
I still haven't got a scope, hopefully next pay day I can pick one up.
I don't have anything with the designations for the parts on on the module. It also appears that there are two different modules. One has components on only one side (the other side has printed resistors only). The other type module has components on both sides.
Ok mine has components on 1 side only with the printed resistors. I just took the time to label everything in a picture. That seems to help me a lot. Having a labeled picture for the ppi driver cards helped me out I know that for sure.
I think I found the problem.
Zoom in on the center of the board.
R32 is reading 1k2. Its supposed to be 51R
Zoom in on the center of the board.
R32 is reading 1k2. Its supposed to be 51R
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Yes I just did that. Now it sounds less distorted but its pretty quiet. There was also 2 bad transistors on that card.
I am going to have to wait til I get a scope. I'm suspecting a bad op amp but I really have no clue.
I am going to have to wait til I get a scope. I'm suspecting a bad op amp but I really have no clue.
If the level is an issue, you can drive a sine wave into both channels and measure the level with a multimeter at various points in the circuit, comparing one channel to the other.
A scope would be required if there was distortion but if it's clean (not sure what 'less distorted' means), a multimeter may work well enough.
A scope would be required if there was distortion but if it's clean (not sure what 'less distorted' means), a multimeter may work well enough.
I just wanted to give a small update. I finally got a cheap Velleman hps5 from Craigslist. It should be OK for now. Anyhow. I traced a clean sine to the input of HB3 then the output only has the bottom half of the sine wave. I just did that really quick before work. I will do a little more investigation when I get back home.
I still have only the bottom half of the waveform after lifting q19
EDIT also it is only doing this when driving the signal into a dummy load. Without a load it is a clean sine wave.
EDIT also it is only doing this when driving the signal into a dummy load. Without a load it is a clean sine wave.
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