MEP-805 Frequency Fluctuation

[Feenix206]

Latest: after finishing all above testing, and not changing anything the 804 A DS7 came on when S5 actuated and output at K1. Im confused i did nothing now it works. Question: does battery voltage come into play? When cold testing bat voltage was running about 22~23v. After all the test tuns it was up to 27v. However on this last failure to get voltage days ago, it happened after a 7hr run so bat voltage was at peak then.

 

[peapvp]

With s1 off and 242a20 removed from s5. I tested diodes cr1 = .471, CR2 =.471, CR3 =

CR3 = 0.51V = OK

 

[peapvp]

No, it wouldn’t make any difference.

you should have around 22V to 27V on the Anode Side when S1 Switch in Run/Prime Position


this would be on Terminal 5 of S5
You should have 0.5 V less on Terminal 2 and on Terminal 3 of S5
You should also have this Voltage on K8 terminals 11 and 12 and on K13 terminals 7 and 1
If you test in this sequence then you are following the exact voltage path of this circuit.
It is not uncommon that the switches, terminals, relay sockets etc are dirty, corroded or loose. The S5 switch is also suspect to wear and so is K1 itself

Just removing one wire can make or brake a circuit, which may have happened here in your case and the thing started to work again for the moment

 

[Feenix206]

No, it wouldn’t make any difference.

you should have around 22V to 27V on the Anode Side when S1 Switch in Run/Prime Position

View attachment 901953
this would be on Terminal 5 of S5
You should have 0.5 V less on Terminal 2 and on Terminal 3 of S5
You should also have this Voltage on K8 terminals 11 and 12 and on K13 terminals 7 and 1
If you test in this sequence then you are following the exact voltage path of this circuit.
It is not uncommon that the switches, terminals, relay sockets etc are dirty, corroded or loose. The S5 switch is also suspect to wear and so is K1 itself

Just removing one wire can make or brake a circuit, which may have happened here in your case and the thing started to work again for the moment

where might I find a complete wiring diagram that you pictured above. That would be helpful next time tracing down the path.

 

[peapvp]

The wiring diagrams start on pdf page 331 of 365
You will find everything on those pages 331 ff