xeawr
Well-known member
Dear friends,
I have a big problem :'( (but probably easy for you guys) and I'm pretty clueless about solving this one. In fact I'm totally desperate. The (used) power supply (for the used Alctron BV300-A) doesn't give out any heater voltage (0.1V instead of 6.7V).
By the way I have two of these microphones + PS, and both have the same problem. All voltages are fine except for the heater voltage. So far I have opened one of the two PS and checked the voltages inside. (see pic below)
When I turn the PS on it gets VERY hot at R15, in fact I think the original R15 died on me, it was all crumbly and measured 7 Ohm (instead of 20 Ohm - see schematic - I would guess?)
I have soldered out and checked three suspicious components:
- L7806CV (is ok, tested with 9V battery)
- C8 (measures fine)
- R15 (replaced by me with 35 Ohm)
Symptoms: Turn PS on, no DC voltage before and after L7806CV, R15 gets VERY HOT
Any hints which components to check next? The other caps surrounding the L7806??
Thanks soooooo much for your help!!!!!!!!!!
I have a big problem :'( (but probably easy for you guys) and I'm pretty clueless about solving this one. In fact I'm totally desperate. The (used) power supply (for the used Alctron BV300-A) doesn't give out any heater voltage (0.1V instead of 6.7V).
By the way I have two of these microphones + PS, and both have the same problem. All voltages are fine except for the heater voltage. So far I have opened one of the two PS and checked the voltages inside. (see pic below)
When I turn the PS on it gets VERY hot at R15, in fact I think the original R15 died on me, it was all crumbly and measured 7 Ohm (instead of 20 Ohm - see schematic - I would guess?)
I have soldered out and checked three suspicious components:
- L7806CV (is ok, tested with 9V battery)
- C8 (measures fine)
- R15 (replaced by me with 35 Ohm)
Symptoms: Turn PS on, no DC voltage before and after L7806CV, R15 gets VERY HOT
Any hints which components to check next? The other caps surrounding the L7806??
Thanks soooooo much for your help!!!!!!!!!!