Hello All!
Yesterday i finished one channel for my new Zen V4. I made an unregulated power supply and i followed the instruction in the document from passdiy (PassDiy).
Everything was right, the connections, the capacitor polarity, etc. until i turned it on. When the amp was power on, maybe 30 seconds passed when the resistor R7 exploded (litterally).
I do not know what cause that. I check the connections, and everything seems OK. My first impression is that Q2 is burned too. I will follow Mr. Pass advice and i will search for an answer tomorrow. Meanwhile, someone could help me think what happend? I wanna know what cause the R7 blow up before i replacing it.
Thank you all!
Yesterday i finished one channel for my new Zen V4. I made an unregulated power supply and i followed the instruction in the document from passdiy (PassDiy).
Everything was right, the connections, the capacitor polarity, etc. until i turned it on. When the amp was power on, maybe 30 seconds passed when the resistor R7 exploded (litterally).
I do not know what cause that. I check the connections, and everything seems OK. My first impression is that Q2 is burned too. I will follow Mr. Pass advice and i will search for an answer tomorrow. Meanwhile, someone could help me think what happend? I wanna know what cause the R7 blow up before i replacing it.
Thank you all!
Hi, Here is the images.
Schematic
(schematic.png - Google Drive)
PCB (I made it myself)
(Not Found)
(IMG-7456.JPG - Google Drive)
(IMG-7457.JPG - Google Drive)
Schematic
An externally hosted image should be here but it was not working when we last tested it.
(schematic.png - Google Drive)
PCB (I made it myself)
An externally hosted image should be here but it was not working when we last tested it.
(Not Found)
An externally hosted image should be here but it was not working when we last tested it.
(IMG-7456.JPG - Google Drive)
An externally hosted image should be here but it was not working when we last tested it.
(IMG-7457.JPG - Google Drive)
Last edited by a moderator:
I attach two pictures with a close up of the resistor.
This is the pdf with the pcb pattern.
ZV4 layout.pdf - Google Drive
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
This is the pdf with the pcb pattern.
ZV4 layout.pdf - Google Drive
gate resistor scorched , mean mosfet is Dodo
first with diode test check for shorts , desolder what's suspicious , replace what's Dodo
check values/position of every resistor
check every semiconductor with diode/short test
it's hard to tell what you did wrong ...... short between mosfet case and heatsink , wrong value somewhere , wrong position of part somewhere ...... plenty of possibilities to do wrong
first with diode test check for shorts , desolder what's suspicious , replace what's Dodo
check values/position of every resistor
check every semiconductor with diode/short test
it's hard to tell what you did wrong ...... short between mosfet case and heatsink , wrong value somewhere , wrong position of part somewhere ...... plenty of possibilities to do wrong
Thanks Zen Mod !!
I followed your advice and I already have a functional channel (so far).
First I checked all the diodes and all was fine.
Second, I checked the ZTX450 and this was fine (i changed it anyway).
Then I check the three Mosfet IRFP044, and two of them it seems were burned. I check their voltages and they were not the expected ones according to Mr. Pass's article, so I changed all the IRFP044, just in case.
After that, I redid all the connections to ground. I change the wires to ground and tried to make a star ground connection.
And finally, I changed all the washers that hold the PCB and the Mosfets to the heat sink. I double checked if they are isoleted from the heat sink.
Yesterday I lit it again, and for now nothing burns. I checked the voltage across the circuit and everything is in accordance with the Mr. Pass's article. I have not connected it to a speaker yet, so I do not know if it's really functional.
One thing that I realize is that the channel I kept it on for 15 or 20 minutes and the mosfets (IRFP044) do not heat up. This is normal?
I followed your advice and I already have a functional channel (so far).
First I checked all the diodes and all was fine.
Second, I checked the ZTX450 and this was fine (i changed it anyway).
Then I check the three Mosfet IRFP044, and two of them it seems were burned. I check their voltages and they were not the expected ones according to Mr. Pass's article, so I changed all the IRFP044, just in case.
After that, I redid all the connections to ground. I change the wires to ground and tried to make a star ground connection.
And finally, I changed all the washers that hold the PCB and the Mosfets to the heat sink. I double checked if they are isoleted from the heat sink.
Yesterday I lit it again, and for now nothing burns. I checked the voltage across the circuit and everything is in accordance with the Mr. Pass's article. I have not connected it to a speaker yet, so I do not know if it's really functional.
One thing that I realize is that the channel I kept it on for 15 or 20 minutes and the mosfets (IRFP044) do not heat up. This is normal?
without sole picture visible in thread , I'm not even sure that you're real person ...... 
if you have around 0V66 where marked in Papa's schematic and if there is approx. 22V potential .......... then you're good and you have gargantuan sized heatsinks , or damn thick palm skin
proceed with second channel in same manner
if you have around 0V66 where marked in Papa's schematic and if there is approx. 22V potential .......... then you're good and you have gargantuan sized heatsinks , or damn thick palm skin
proceed with second channel in same manner
Jajajajaja, i'am a real person....
Today i turned it on again and this time i connect it to a speaker but nothing is heard, not sound at all (even hum). All the IRFP044 don't even get hot after 30 minutes of turned on. It seems hat all IRFP044 are not working at all.
All voltages a are ok, so am out of ideas....
For input, i put an old MP3 player that i use in my tests.
Today i turned it on again and this time i connect it to a speaker but nothing is heard, not sound at all (even hum). All the IRFP044 don't even get hot after 30 minutes of turned on. It seems hat all IRFP044 are not working at all.
All voltages a are ok, so am out of ideas....
For input, i put an old MP3 player that i use in my tests.
Hi again!
I was away for a while due to my vacation but in the meanwhile i made some detective work. I figured out that R0 and R1 was burned too so this the reason why theres was not current. I made a new attemp after replaced R0 and R1 and finally I get the amp working with all mosfets warming immediatly . Everithing was fine and all the voltages are correct for about 30 minutes.
After this i shut off for proceed to adjust R4. When i power up again, i wait for 1 minute and before i put the DMM's probes, the amp fails again in the same way but this time R0 and R1 blows up first (this time with a big spark and smoke) and after that R7 . Disarm all over again and i take a look on the Mosfets descovering that all was burned (all IRFP044). My theory is the mosfets are causing the resistors burning because a short circuit. I measure the resistance between source and drain and all have a short (0 ohm).
My first posibly cause is inrush current. It was difficult to get any thermistor similar to CL-60 here in Chile (like shown in schematic) so i power up without this component. Can inrush current damage all the mosfets?
I read some forums here that IRFP044 are very sensitive to statics so this is the second cause in my list. I passed for this before with a gainclone made with a TDA2050. In that time, the solution was replace the chips with another brand because the first one was from a chinese dealer. The mosfets am using are Infineon, Is it a reliable brand?
Maybe i'm missing something else?
This for now, now i waiting for the delivery of the replacements components.
I was away for a while due to my vacation but in the meanwhile i made some detective work. I figured out that R0 and R1 was burned too so this the reason why theres was not current. I made a new attemp after replaced R0 and R1 and finally I get the amp working with all mosfets warming immediatly
. Everithing was fine and all the voltages are correct for about 30 minutes.After this i shut off for proceed to adjust R4. When i power up again, i wait for 1 minute and before i put the DMM's probes, the amp fails again in the same way but this time R0 and R1 blows up first (this time with a big spark and smoke) and after that R7
. Disarm all over again and i take a look on the Mosfets descovering that all was burned (all IRFP044). My theory is the mosfets are causing the resistors burning because a short circuit. I measure the resistance between source and drain and all have a short (0 ohm). My first posibly cause is inrush current. It was difficult to get any thermistor similar to CL-60 here in Chile (like shown in schematic) so i power up without this component. Can inrush current damage all the mosfets?
I read some forums here that IRFP044 are very sensitive to statics so this is the second cause in my list. I passed for this before with a gainclone made with a TDA2050. In that time, the solution was replace the chips with another brand because the first one was from a chinese dealer. The mosfets am using are Infineon, Is it a reliable brand?
Maybe i'm missing something else?
This for now, now i waiting for the delivery of the replacements components.
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