Batboard

We have about 8 or 10 four channel HT750's that are exhibiting the same on\off\logic problem. Even when the on\off switch is in the 'off' position when battery voltage is applied, the unit will still power on; you see the top LED light green and you can hear it give a power up "beep" At this point the radio doesn't function but when you actually turn the switch to the 'on' position there is no re-power up sequence and the unit remains DOA. However if you apply battery voltage while the on\off switch is already in the 'on' position the power up sequence occurs normally and the unit works fine Transmit and Receive ........... until you switch the on\off switch to 'off' .....then it will not power back up again when switched 'on' until battery voltage is removed and re-installed with the on\off switch 'on'. We sent one in for factory repair thinking we could use it as a model to repair the other 8 or 9 units, but the factory simply replaced the whole board (complete). Unfortunately we do not have that luxury. They are all out of warranty and $284.00 per unit is not feasible. Factory says they never heard of this problem before ???
Any help anyone??

Have you actually tried to replace the volume control pot? It's pretty easy and the pots are only about $3-4

It sounds like Q400, the main B+ switch is either shorted or leaking.

Regards,

Allen

Got one the same way right down to the tee of what you just posted

should be easy ...check the switch and either replace or go to the transistor mentioned. I think Q400 may be under a shield IIRC but I haven't looked at the manual lately

should be easy ...check the switch and either replace or go to the transistor mentioned. I think Q400 may be under a shield IIRC but I haven't looked at the manual lately