Hi,
This is my first post. I need help repairing an RF T1500-BD that's not producing sound. It powers up fine with a rail of 76.4V. So far, with the help of tips I've gained from other posts here, I've measured the following on the U2000 and U2002 ICs:
U2000
Pin 1: 0.5V
Pin 2: 1.35V
Pin 3: 0.0
Pin 4: 0.195
Pin 5: 0.52
Pin 6: 4.9
Pin 7: 0.61
Pin 8: 7.0
U2002
Pin 1: 0.5V
Pin 2: 2.39V
Pin 3: 0.0
Pin 4: 0.197
Pin 5: 0.999
Pin 6: 4.6
Pin 7: 1.12
Pin 8: 6.93
Q2000, 2001, 2010, 2012 were measuring -6, +6, +8 and +8 respectively.
U2000 and U2002 were hot to the touch and based on the measured readings above, at the very least U2000 seemed defective so I removed it. this improved the voltage to 11.6 and 11.6 for q2010 and 2012 - and lowered the current demand on my power supply ( from around 2A to about 1A).
I've since removed U2002 as I was still not getting the correct voltage at pin 4. This did not help as this voltage is still not present, even at the BD output board. This tells me there is also a problem on the BD output board and I'd have to remove it to check and repair - I hate removing these boards - any tips in removing it is welcomed.
Could you guide me as to what to look for on this board or what else could be causing this issue? Thanks.
This is my first post. I need help repairing an RF T1500-BD that's not producing sound. It powers up fine with a rail of 76.4V. So far, with the help of tips I've gained from other posts here, I've measured the following on the U2000 and U2002 ICs:
U2000
Pin 1: 0.5V
Pin 2: 1.35V
Pin 3: 0.0
Pin 4: 0.195
Pin 5: 0.52
Pin 6: 4.9
Pin 7: 0.61
Pin 8: 7.0
U2002
Pin 1: 0.5V
Pin 2: 2.39V
Pin 3: 0.0
Pin 4: 0.197
Pin 5: 0.999
Pin 6: 4.6
Pin 7: 1.12
Pin 8: 6.93
Q2000, 2001, 2010, 2012 were measuring -6, +6, +8 and +8 respectively.
U2000 and U2002 were hot to the touch and based on the measured readings above, at the very least U2000 seemed defective so I removed it. this improved the voltage to 11.6 and 11.6 for q2010 and 2012 - and lowered the current demand on my power supply ( from around 2A to about 1A).
I've since removed U2002 as I was still not getting the correct voltage at pin 4. This did not help as this voltage is still not present, even at the BD output board. This tells me there is also a problem on the BD output board and I'd have to remove it to check and repair - I hate removing these boards - any tips in removing it is welcomed.
Could you guide me as to what to look for on this board or what else could be causing this issue? Thanks.
Chipquik for removing the boards.
Do you have a scope?
Q2010 and Q2012 are in parallel.
What is the DC voltage on the collectors of Q2010/12?
Do you have a scope?
Q2010 and Q2012 are in parallel.
What is the DC voltage on the collectors of Q2010/12?
Thanks Perry.
Collector voltage 24.6
Yes I have access to a scope - haven't used one in quite a while though.
Collector voltage 24.6
Yes I have access to a scope - haven't used one in quite a while though.
Thanks for your response Perry.
I Sent a reply earlier but not seeing it, not sure what happened.
I have access to a scope.
Collector voltage on Q2010/12: 24.6V
I Sent a reply earlier but not seeing it, not sure what happened.
I have access to a scope.
Collector voltage on Q2010/12: 24.6V
You're still under moderation which means that your first posts have to be OK'd by a moderator.
Looking at the back of the BD driver board, the two pins at the far left are signal and ground. Do you have signal being driven into the BD driver board?
Looking at the back of the BD driver board, the two pins at the far left are signal and ground. Do you have signal being driven into the BD driver board?
Sorry for taking so long, had to run out. Yes, I have signal being driven into the BD Driver board - a clean, amplified sine wave of my input.
Do you have rail-rail oscillation on the output transistors?
I think that there are 3 BD boards used in these amps. One has the device highlighted in the image below. One is a double-stacked board and one is a single board without the device highlighted in the image below. Which do you have?
I think that there are 3 BD boards used in these amps. One has the device highlighted in the image below. One is a double-stacked board and one is a single board without the device highlighted in the image below. Which do you have?
Attachments
Someone had a similar amp with a dead HC74 but had output on neither drive pin. I have a t1500 that I need to repair but the estimate hasn't yet been approved. If it gets approved, I'll let you know what I find.
OK thanks. I'll go ahead and remove the board for further checks. Do you have a schematic could share?
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No. The last time I checked, Rockford had not released it.
The following post may be of some help.
http://www.diyaudio.com/forums/car-audio/293381-rockford-p1000-1bd-help-schematic.html#post4762294
The following post may be of some help.
http://www.diyaudio.com/forums/car-audio/293381-rockford-p1000-1bd-help-schematic.html#post4762294
Thanks, that looks like it will help. It will take me some time to get the parts though. Will update you.
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Do you have any experience removing the boards from amps like this?
A pulled or damaged via can cause all sorts of strange problems.
A pulled or damaged via can cause all sorts of strange problems.
Pulled one before, wasn't a good experience. But I saw a video of someone using the chipquik you recommended (was the flux paste). Will be using that approach.
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