I'm repairing an Audio System X-Ion 280.2.
Except everything wrong with it, i'm missing the rectifiers.
I've checked the service manual about the audio system twister series and it says FEP16DT in all location (picture attached). I guess this amp just uses 4 of them instead 2, as it's a bigger version.
Then I've tried to source them but with no avail, seems that they are obsolete. I'm pretty sure I need the ones in circled in blue in the second picture in the fairchild datasheet ? Why does Vishay only have 1 variant ? I'm a bit confused...
Any ideas what can I use as a substitute ?
Except everything wrong with it, i'm missing the rectifiers.
I've checked the service manual about the audio system twister series and it says FEP16DT in all location (picture attached). I guess this amp just uses 4 of them instead 2, as it's a bigger version.
Then I've tried to source them but with no avail, seems that they are obsolete. I'm pretty sure I need the ones in circled in blue in the second picture in the fairchild datasheet ? Why does Vishay only have 1 variant ? I'm a bit confused...
Any ideas what can I use as a substitute ?
Attachments
I don't see a sub.
I don't know what you mean about one variant. The doubler has (had) a range of voltages.
They are available in higher voltage ratings from some distributors according to octopart but I don't know if it's worth the effort to buy from them.
Have you tried contacting the manufacturer for options?
I don't know what you mean about one variant. The doubler has (had) a range of voltages.
They are available in higher voltage ratings from some distributors according to octopart but I don't know if it's worth the effort to buy from them.
Have you tried contacting the manufacturer for options?
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Finally the FEP16DT arrived couple of days ago.
I've pulled out all of the output mosfets, 2 shorted.
Then I've had to replace almost every transistor in section attached and most of the resistors (most of them were way beyond 5% tolerance, some were totally open).
I've reached something like a dead end.
The AH-16/BH-16 (the sot223 package) drivers, new ones, are getting incredibly hot even with or without the output mosfets (bias is set to minumum). Left like that for 30 seconds and they short and I have to start all over from the start checking and replacing resistors, sot-23 and sot-223 transistors, small cmd caps and etc.
The rail voltages, the aux +-15v, and +- 6.6v at the ic in the middle are all fine and stable.
At the drivers AH-16/BH-16 I do have 0.5v~0.6v base to emitter junction.
Any idea why they are always frying ?
The only thing i've not changed with new ones are the diodes dp20 and dp21 (they read fine), no idea what they are....maybe 1n4148 ?
I've pulled out all of the output mosfets, 2 shorted.
Then I've had to replace almost every transistor in section attached and most of the resistors (most of them were way beyond 5% tolerance, some were totally open).
I've reached something like a dead end.
The AH-16/BH-16 (the sot223 package) drivers, new ones, are getting incredibly hot even with or without the output mosfets (bias is set to minumum). Left like that for 30 seconds and they short and I have to start all over from the start checking and replacing resistors, sot-23 and sot-223 transistors, small cmd caps and etc.
The rail voltages, the aux +-15v, and +- 6.6v at the ic in the middle are all fine and stable.
At the drivers AH-16/BH-16 I do have 0.5v~0.6v base to emitter junction.
Any idea why they are always frying ?
The only thing i've not changed with new ones are the diodes dp20 and dp21 (they read fine), no idea what they are....maybe 1n4148 ?
Attachments
Yes and yes.
They overheat with the bias jumper in place. All of the drivers both channels. Idle current goes to 2A....I've repaired another one of these and without the outputs in place it should be around 0.7~0.8A
They overheat with the bias jumper in place. All of the drivers both channels. Idle current goes to 2A....I've repaired another one of these and without the outputs in place it should be around 0.7~0.8A
Previously, were you using the same batch of transistors as you are in this amp?
Are the two op-amps overheating?
Do you see any excessive noise or oscillation on any of the pins of those two op-amps?
Are the two op-amps overheating?
Do you see any excessive noise or oscillation on any of the pins of those two op-amps?
Previously, were you using the same batch of transistors as you are in this amp? - first time same batch they all fried, second time 7 same batch and 1 is from a different one as i've ended my supplies in sot223 package.
Are the two op-amps overheating? - No.
Do you see any excessive noise or oscillation on any of the pins of those two op-amps? - there is some noise on pin 1 on both op amps, but i don't see anything on pin 2 and 3.
I've already tried with new op amps, but with no avail.
Are the two op-amps overheating? - No.
Do you see any excessive noise or oscillation on any of the pins of those two op-amps? - there is some noise on pin 1 on both op amps, but i don't see anything on pin 2 and 3.
I've already tried with new op amps, but with no avail.
Removed all of the drivers...no more heating, no more high current at idle. Tested each one of the drivers on the transistor tester. All are fine with Hfe over 200.
When i got the amp, most of the small sot23 were barely readable. Maybe there is a chance i've swapped somewhere NPN with the PNP transistor in the differential section.
Red ones are NPNs and the green ones are PNP's....
I'm trying to compare it to the audio_system_f2-190.pdf schematic....but it seems the last one does not have drivers/buffer transistors and it's a little bit different than X-ion series.
Red ones are NPNs and the green ones are PNP's....
I'm trying to compare it to the audio_system_f2-190.pdf schematic....but it seems the last one does not have drivers/buffer transistors and it's a little bit different than X-ion series.
