Hello again guys !
Ground Zero GZRA 1.1650D - blown output, no gate drive even if a feed a strong RCA signal.
Voltages are OK at pads. PS section is OKAY.
Have to change to IC-U509, as this one gives out the gate drive directly to IRFB4227 - but it's scratched. This is the first time i ever see this chip used in class D.
U 108 is 74HC02D.
Can anybody give a clue ?
Pictures attached.
Ground Zero GZRA 1.1650D - blown output, no gate drive even if a feed a strong RCA signal.
Voltages are OK at pads. PS section is OKAY.
Have to change to IC-U509, as this one gives out the gate drive directly to IRFB4227 - but it's scratched. This is the first time i ever see this chip used in class D.
U 108 is 74HC02D.
Can anybody give a clue ?
Pictures attached.
Attachments
The IR2010, IR2110 and IR2113 all have the same pin configuration. Their specs are close but not exact so to get the right one, you may have to try all of them. The 2010 is only 200v so that may eliminate it if the rail voltage is too high.
A friend of mine gave me a hint that the IC could be really tnd505, not an IRS. But I can't find tnd505 anywhere to be available ?
I've found an old thread over here about other amp, but using IR2110 as an substitute to tnd505 with few mods. I will quote "However, what I had to do was join the Ground and Common together on the IR2110. Worked great."
Thread is here.
Pioneer GM-D8500M
I've found an old thread over here about other amp, but using IR2110 as an substitute to tnd505 with few mods. I will quote "However, what I had to do was join the Ground and Common together on the IR2110. Worked great."
Thread is here.
Pioneer GM-D8500M
I've used IR2113SPBF.
Strong gate drive is present and the voltages are correct at all pins.
But as soon as I mount IRFB4227 they heat up like for 5-10 seconds and there is excessive current draw.
Strong gate drive is present and the voltages are correct at all pins.
But as soon as I mount IRFB4227 they heat up like for 5-10 seconds and there is excessive current draw.
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Clamp them to the heatsink so you don't damage them.
Is the drive good at the FET gate legs for all output FETs?
Are the outputs new and from a reputable distributor?
Is the drive good at the FET gate legs for all output FETs?
Are the outputs new and from a reputable distributor?
Low side - YES all 4 of them.
High side, can't be seen when there are no FETs mounted.
Output mosfets are from Farnell
High side, can't be seen when there are no FETs mounted.
Output mosfets are from Farnell
You can use a 9v battery to supply the high-side to see signal without the FETs.
You said that the amp draws current and has good signal on both the high and low side. Did you pull the FETs?
You said that the amp draws current and has good signal on both the high and low side. Did you pull the FETs?
You said you had 5-10 seconds before the FETs heated up. Clamping them should give more time.
You stated that you couldn't see the high-side drive without the outputs and als osaid you checked the drive. Which is it?
You stated that you couldn't see the high-side drive without the outputs and als osaid you checked the drive. Which is it?
Sorry. I'm having bad days lately due to the lack of sleep and other personal stuff.
I've checked only the low side and I guessed that high side would be fine too.
But I've found some more issues. The relay was terribly burnt from it's bottom side when I pull it out of the board. The bottom plastic shell was badly melted.
Then i found the diodes here - D103 and D106 are shorted when i pulled them out.
I've tried to look up at the markings with a magnifying glass but could not read anything. I have a stack of 1n4148w/100v, would this ones work ?
Taking the relay out, removing D103 and D106, and using only one mosfet per side (bank) I managed to make the amplifier stable and working. No issues.
So diodes have to be changed and new relay.
I've checked only the low side and I guessed that high side would be fine too.
But I've found some more issues. The relay was terribly burnt from it's bottom side when I pull it out of the board. The bottom plastic shell was badly melted.
Then i found the diodes here - D103 and D106 are shorted when i pulled them out.
I've tried to look up at the markings with a magnifying glass but could not read anything. I have a stack of 1n4148w/100v, would this ones work ?
Taking the relay out, removing D103 and D106, and using only one mosfet per side (bank) I managed to make the amplifier stable and working. No issues.
So diodes have to be changed and new relay.
Attachments
The 1n4148 is commonly used but if one is shorted and there are other FETs in the bank, I'd replace all of the pulldown diodes (parallel to the 18 ohm) in that bank so they drive the FETs precisely the same.