After a second look I realized this waveform should be the same as Pin 7 IC11. Recheck it to be sure.
Yes to Pin 1 should look like Pin 7
ZD5=12v, ZD4=24v & ZD3=12v If you measure from ZD5 anode to ZD3 cathode it should be 50 volts.
The diodes ZD3 & ZD5 are 12 volt zener diodes, ZD4 is a 24 volt zener diode. ZD7 is an 11 volt zener diode. In order for these circuits to work you must maintain this arrangement.
Do Not Use a 1N4148 diode!! And unless you know what to expect Do Not Change Around the diodes and capacitors. Your liable to cause more damage and your haphazard procedure makes it hard to help you.
Not trying to discourage you, I know from past experience you will be able to repair this amp, if you take it step by step. If your not sure ask and I will get back to you as time permits.
If your measuring 41 volts at the cathode of ZD4 and ZD3 it appears that ZD3 is shorted or something in parallel with it.
Recheck ZD3, ZD4 and ZD5 with a voltmeter each one individually,black probe on anode red probe on cathode and post your measurements as follows:
Fill in the blanks
ZD3- +/-__volts
ZD4- +/-__volts
ZD5- +/-__volts
Do Not Use a 1N4148 diode!! And unless you know what to expect Do Not Change Around the diodes and capacitors. Your liable to cause more damage and your haphazard procedure makes it hard to help you.
Not trying to discourage you, I know from past experience you will be able to repair this amp, if you take it step by step. If your not sure ask and I will get back to you as time permits.
If your measuring 41 volts at the cathode of ZD4 and ZD3 it appears that ZD3 is shorted or something in parallel with it.
Recheck ZD3, ZD4 and ZD5 with a voltmeter each one individually,black probe on anode red probe on cathode and post your measurements as follows:
Fill in the blanks
ZD3- +/-__volts
ZD4- +/-__volts
ZD5- +/-__volts
Ok I ordered the required parts and more ceramic capacitors. I have the 11v, just not the 12v-24v. Glad I verified that. The small zenners, that are reading a short as well what are they rated.? So can order those as well. Once the rated parts come in I will install per your directions and pick up the thread from there.
Just to clarify that when filling in the blanks, I expect the voltages to all be positive (+) if the probes are placed as I stated.
I can't really say for sure what make of diode is in the CXA18001 but here are three I found on Mouser. 11v 12v and 24v .5 watt 5% 0805 smd
You won't need the 11v as I'm sure ZD7 is good. These are 1/2 watt. I mentioned 1 watt in a previous post, but 1/2w is plenty.
Mouser or Digikey is your best bet. If you can't find the Vishay in stock, just be sure to get 1/2 watt or better, 5%, 0805's. If you find something that isn't barrel shaped as long as its an 0805 SMD and has the same zener voltage and .5 watt rating at 5% they will do.
TZQ5242B-GS18 Vishay Semiconductors | Mouser
TZQ5252B-GS08 Vishay Semiconductors | Mouser
TZQ5241B-GS18 Vishay Semiconductors | Mouser
You won't need the 11v as I'm sure ZD7 is good. These are 1/2 watt. I mentioned 1 watt in a previous post, but 1/2w is plenty.
Mouser or Digikey is your best bet. If you can't find the Vishay in stock, just be sure to get 1/2 watt or better, 5%, 0805's. If you find something that isn't barrel shaped as long as its an 0805 SMD and has the same zener voltage and .5 watt rating at 5% they will do.
TZQ5242B-GS18 Vishay Semiconductors | Mouser
TZQ5252B-GS08 Vishay Semiconductors | Mouser
TZQ5241B-GS18 Vishay Semiconductors | Mouser
The voltages across ZD4 & ZD3 indicates that C61-100nf is bad.
Even though it reads in value you should replace it. I have seen this exact failure multiple times.
It is possible IC10-TL072 may be shorted Pin 8 to Pin 4, and is dragging down the voltages across ZD4 & ZD3. If necessary replace it but I would definitely replace C61.
Leave R175 out of circuit. You won't need to replace until you have the Ladder Circuit fixed. And when you do, also check R173, 174, 273, 274- 16 ohm.
Are you sure the zener diode is ZD10?
Even though it reads in value you should replace it. I have seen this exact failure multiple times.
It is possible IC10-TL072 may be shorted Pin 8 to Pin 4, and is dragging down the voltages across ZD4 & ZD3. If necessary replace it but I would definitely replace C61.
Leave R175 out of circuit. You won't need to replace until you have the Ladder Circuit fixed. And when you do, also check R173, 174, 273, 274- 16 ohm.
Are you sure the zener diode is ZD10?
So I replaced the ic9 because I did have short between pins 4-9. Still the pins are shorted? Also, zd11 is 16.5vdc so Ishould i use 17v in zd10. C60 I will replace it as well just need the value? And I ordered to incorrect parts for the capacitors so I sent off a new order yesterday, mouser parts usually arrive in 3 days.
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