- Jan 31, 2018
- Reaction score
- My Satellite Setup
50E - 30W
2x CM 1.2m Polar Mount/Jack
Gibertini 1m OP100 - STAB HH100 - Inverto Black Ultra 0.2 Twin
Edision Primo IP S2
Venton Unibox HD2
Sony Bravia 55" 4K
- My Location
- South Wales
I read the post on the other forum you just linked to, when I said it's there for current limiting its to limit the power drawn from the STB, especially if there is a fault condition. The 7805 doesn't need it normally, however it can sink 1amp (Or more depending on flavor) which you do not want on your STB!Thanks, RustySpoons. I will check that.
Also the collector pin of transistor Q2 seems to have been hot (it's a bit blackened). Could that part of the circuit have something to do with the burning of R20, too?
Photos of my circuit board with burnt R20 can be seen at the dutch forum: STAB HH100 onderdeeltje doorgebrand
Also the "dossier technique" of the HH100, complete with circuit diagram, is there: It's not too large to be uploaded to sat4all.com!
And another forum member has reported a motor with a defective R20 there. Is the R20 not dimensioned well in these motors? Should it have a greater resistance value, or be able to handle (dissipate) more power?
Check Q2 to see if it reads correctly on diode setting with multimeter, resistance setting will tell you if it's completely gone however but will not show if it's functioning.
When you fit the replacement R20 stand it up longer on its legs so it's off the PCB, it will get better airflow, not char the board and the legs will also help dissipate heat. No harm in going up with current capability, i.e. 1w instead of 1/2w etc (Not sure whats fitted). But I wouldn't mess around with the value.