Aside from this an incandescent light bulb has low resistance when cold, so allowing semi's in the DUT enough time to blow up.
Sometimes I put resistors in series with the rails to limit the current. However checking, double checking and triple checking before pulling the switch remains my favorite way to prevent damage.
Morning.
I have a problem with one channel. It was much hotter than the other one for some time. Measured by a laser thermometer there was a 5 C difference around one area. I did not use the amp for a few weeks because I was working on a DAC and yesterday after test connecting it one amp side got hot instantly and music from one channel was significantly louder, like an open gain.
For now, I disconnected everything and need guidance on where to begin troubleshooting.
(DAC might be causing a problem, that is for sure- as a minimum I should reduce gain to 1.4V down from 2.4V, but I still need to find out why the amp is getting hot).
Thank you
I have a problem with one channel. It was much hotter than the other one for some time. Measured by a laser thermometer there was a 5 C difference around one area. I did not use the amp for a few weeks because I was working on a DAC and yesterday after test connecting it one amp side got hot instantly and music from one channel was significantly louder, like an open gain.
For now, I disconnected everything and need guidance on where to begin troubleshooting.
(DAC might be causing a problem, that is for sure- as a minimum I should reduce gain to 1.4V down from 2.4V, but I still need to find out why the amp is getting hot).
Thank you
Just checked with no load everything disconnected. It is hot at Q112, Q110, Q113. To me the hottest one is Q112.
TP1 to TP2: 5.95 V (decreasing slowly)
TP3 to TP 4: 0.196V
TP105 to V= is 1.35V
TP106 to V- is 51.35V !!!
Something is seriously wrong
TP3 to TP 4: 0.196V
TP105 to V= is 1.35V
TP106 to V- is 51.35V !!!
Something is seriously wrong
I don't have alot of time right now but maybe start with pulling out and checking Q102
R113
D116 or R131
If the checkout please pull out and check Q105, Q106
We can go from there.
If those all check out it ok it maybe worth checking out the IPS in isolation just to be sure it's functioning OK before we explore the ops any further.
Good luck 👍
Just lift one end of resistors and diodes
You do have to completely remove transistors, or at least totally disconnect two of the three leads (three of four for dual gate or other special types) in order to have any confidence. It's easier to pull it and test out of circuit. A diode test will only show you a complete failure, like a short or open.
A component in circuit often has other devices in parallel, so that is what you measure in circuit. With tubes, the component is basically an open circuit with no heater or other voltages applied. Parts connected only to the tube could be measured in circuit. With solid state this is not the case.
Always be certain that what you are measuring is what you intend to measure. Being lazy will only send you down the wrong path with incorrect conclusions.
A component in circuit often has other devices in parallel, so that is what you measure in circuit. With tubes, the component is basically an open circuit with no heater or other voltages applied. Parts connected only to the tube could be measured in circuit. With solid state this is not the case.
Always be certain that what you are measuring is what you intend to measure. Being lazy will only send you down the wrong path with incorrect conclusions.
I would also only install one NPN and one PNP output when first connecting the tested IPS to the output board. See if it behaves, then install the other outputs. This way only two outputs go up in smoke if something undetected is wrong.
My EF3-3 its up and running in a multiamped system.
No hum and beautifull sound.
Ambient temperature 31C° heatsinks temperature after 7 hours are 51C°.
Thank you at the team for the great amp.
giorgio
No hum
No hum and beautifull sound.
Ambient temperature 31C° heatsinks temperature after 7 hours are 51C°.
Thank you at the team for the great amp.
giorgio
No hum
It is so hard to remove 3 leg devices.
I ll pause for now.
R113 1.5r
D116 0.237V, reverse leads - no continuity
I ll pause for now.
R113 1.5r
D116 0.237V, reverse leads - no continuity