OK, I added the battery, open switch, it didn't go in protection mode. R2 reads 1.33V & R3 reads 0.51V
-
Categories
-
Platforms
-
Content
OK, I added the battery, open switch, it didn't go in protection mode. R2 reads 1.33V & R3 reads 0.51V
I tried to understand why we get such confusing readings from the diodes.
The answer is the schematics and the actual PCB are in disagreement !
1. In the schematics the diodes that have their anodes connected are D9 and D10
while in the PCB they are D8 and D11.
2. In the schematics the diodes that have their cathodes connected are D8 and D11
while in the PCB they are D9 and D10.
We shall leave it at that.
The answer is the schematics and the actual PCB are in disagreement !
1. In the schematics the diodes that have their anodes connected are D9 and D10
while in the PCB they are D8 and D11.
2. In the schematics the diodes that have their cathodes connected are D8 and D11
while in the PCB they are D9 and D10.
We shall leave it at that.
Last edited:
Well,
it looks like the batteries are (EDIT)NOT connected properly,they should be in series to produce the 3.25V as in #105.
Could you please check that again.
So is the capacitors causing the issue? Anything I can do with the parts I already have? Should I go get some new capacitors or try some different rating resistors?
I don't have the switch on the jig closed. Maybe that's why?
It is most likely that the capacitors are faulty one or bot
Are the batteries connected in series?
Is the voltage produced by the batteries "at the 2.2K resistor" 3.25V ?
Are the batteries connected in series?
You can try with the switch closed as well.
I have the jig assembled just like in the schematic you made, the batteries read 3.32V.
OK, as soon as i connected the switch, it went into protection mode and I checked the R2 & R3 Voltages again in protection mode and R2 reads 1.56V & R3 reads 0.58V
OK cool, I'll let you know how it comes out. I'll be back soon. Thanks
OK, I got new capacitors installed. The amp still goes into protection mode.
73's de Edd
- Aug 21, 2015
- 3,629
- Joined
- Aug 21, 2015
- Messages
- 3,629
.
Sir Rick79. . . . . . .
Good show !
What with that cap meter not working for you, that replacement is about the only way to know, when you are dealing with the equivalency of a non polarized electrolytic.
Did you ever get to my mention of establishing the cut out point with establishing a marked reference position on the volume control ?
Or maybe, you have done it sooooooo many times, that you just KNOW where it is . . .relatively.
Can you now get the unit operational, in the respect of getting the unit to cut out with volume advance until cut off..
Then you shut down and jumper across R3 and do a quick run up of the volume again, to confirm that the amp might NOT go into cut off at all, this test time.
If so PULL the jumper from across R3.
Then I hope that you bought more than 2 of those caps to go ahead and observe its install polarity and solder tack a new unit across C12 position and test for cut off. If that has no result, un tack it and sub it in across C10 position and test for cut out.
The last test position, if required, would be to sub it across C7 position .
However, that last positions function, is more relatable to causing your difficulty in getting the unit to eventually / reliably latch on during system power up.
Should you have only bought 2 of those new capacitors I think that we might gamble on using either of the
two pulled / replaced capacitors with short wire extensions soldered on to facilitate connecting the other ends..
Thasssit
73's de Edd
.
Sir Rick79. . . . . . .
Good show !
What with that cap meter not working for you, that replacement is about the only way to know, when you are dealing with the equivalency of a non polarized electrolytic.
Did you ever get to my mention of establishing the cut out point with establishing a marked reference position on the volume control ?
Or maybe, you have done it sooooooo many times, that you just KNOW where it is . . .relatively.
Can you now get the unit operational, in the respect of getting the unit to cut out with volume advance until cut off..
Then you shut down and jumper across R3 and do a quick run up of the volume again, to confirm that the amp might NOT go into cut off at all, this test time.
If so PULL the jumper from across R3.
Then I hope that you bought more than 2 of those caps to go ahead and observe its install polarity and solder tack a new unit across C12 position and test for cut off. If that has no result, un tack it and sub it in across C10 position and test for cut out.
The last test position, if required, would be to sub it across C7 position .
However, that last positions function, is more relatable to causing your difficulty in getting the unit to eventually / reliably latch on during system power up.
Should you have only bought 2 of those new capacitors I think that we might gamble on using either of the
two pulled / replaced capacitors with short wire extensions soldered on to facilitate connecting the other ends..
Thasssit
73's de Edd
.
OK, I used a jumper wire across R3 and the amp doesn't go into protection mode.
73's de Edd
- Aug 21, 2015
- 3,629
- Joined
- Aug 21, 2015
- Messages
- 3,629
.
Sir Rick 79. . . . . .
Then remove the jumper and proceed with the sequential trying of the shunting of 100 ufd of capacitance
across each of my mentioned capacitors, trying it, one capacitor at a time.
73's decision Edd
.
Sir Rick 79. . . . . .
Then remove the jumper and proceed with the sequential trying of the shunting of 100 ufd of capacitance
across each of my mentioned capacitors, trying it, one capacitor at a time.
73's decision Edd
.
Rick ,
The diode tests we did are incomplete for the reasons explained in #122.
In order to get to a conclusion about the diodes, we need to have them marked correctly on the schematics.
Use an ohmmeter in 20K range to measure resistance between R2,R3 and the diodes,to find the way the diodes are actually connected.
Please fill in the "blanks" (in the Blue area of the schematic below) with the diode marks as they are actually connected on the PCB.
Then we can continue.
Fill
The diode tests we did are incomplete for the reasons explained in #122.
In order to get to a conclusion about the diodes, we need to have them marked correctly on the schematics.
Use an ohmmeter in 20K range to measure resistance between R2,R3 and the diodes,to find the way the diodes are actually connected.
Please fill in the "blanks" (in the Blue area of the schematic below) with the diode marks as they are actually connected on the PCB.
Then we can continue.
Fill
It took me a long time tracing the lines on the circuit board, Top and bottom, but I'm pretty sure the diodes are marked correctly now
Attachments
I tried shunting all capacitors one at a time as you mentioned, but the amp still went into protection at the same volume level.
OK I re-opened diode 8, It gives me half an inch more on the volume before going into protection mode.
O.K.
Please mark that point on the "dial".
Now open D10 (cut it like you did for D8).
With both D8 and D10 open,does the amp go into protection?If it does, at what point?
Measure with the DMM in "diode mode test" D8,D10 and invert polarity, what do we get?
Please mark that point on the "dial".
Now open D10 (cut it like you did for D8).
With both D8 and D10 open,does the amp go into protection?If it does, at what point?
Measure with the DMM in "diode mode test" D8,D10 and invert polarity, what do we get?
Similar threads
