Blues jr low voltage problem

[pontiacpete]

Might be time to try a different meter.

Ok with another meter im getting 2.1mA.

[Helmholtz]

Ok with another meter im getting 2.1mA.

So the 2 meters are apart by a factor of 15!
At least one of them is either bad or has a weak battery.

Maybe even the -8V reading was wrong.

[The Dude]

...... and maybe the low voltage reading was meter error from the get go.

[pontiacpete]

So the 2 meters are apart by a factor of 15!
At least one of them is either bad or has a weak battery.

Maybe even the -8V reading was wrong.

I thought you were right for minute here about the meter because i went and took a measurement with another meter and there was -15v on pin 4 of the IC. And was like are we finally done with? Then i put Zener back in and it fell to -6.7v. I hope this info leads to solving this problem.
Also after all that went on today the c34 was bulging quite a bit.
BTW I threw out the batteries in that meter, thanks for pointing that out

[Helmholtz]

Bad or wrong Zener.

[pontiacpete]

Bad or wrong Zener.

Could they labeled wrong? On the body of the diode i can see that it say 4744

[Helmholtz]

Measure the zener voltage using a 1k series resistor.

[pontiacpete]

Can you explain? My brain isn’t working anymore.
Series across the diode in circuit or just any diode from this batch out of circuit

[Helmholtz]

Can you explain? My brain isn’t working anymore.
Series across the diode in circuit or just any diode from this batch out of circuit

Wire 1k in series with the zener and connect to a DCV of maybe 20V.
Measure the voltage across the zener. In one direction you should get 0.7V and in the other the zener voltage.

Most likely you got an 8.2V zener (1N4738A).
Any numbers on the glass body?

[pontiacpete]

Yes there are numbers on the body that say 4744. That’s clearly seen

[g1]

No reason why low voltage would be hard on C34. It's definitely mounted with + end to ground?

[pontiacpete]

I’ve been wondering if there’s something wrong with silk screening on this board

[g1]

D8 anode should connect to (-) terminal of C34.
It is drawn backwards on the rev.A schematic, so the silk screening could be wrong as well.

[pontiacpete]

It might be hard to believe but was thinking the same thinng.
Looking back at the complete service manual I got from Enzo, rev A and rev B are the same and wrong but rev C is drawn correctly anode and positive to ground.
I’m going to do this in the morning

[g1]

rev C is drawn correctly anode and positive to ground.

You mean cathode and positive to ground.