Meter died

[Thermioniclife]

So I had a problem with a meter that was reading to high so I installed the parallel 9.09 resistors and got close to the correct value.
I ran the amps for about 5 hours last evening and they sounded great. But after about 3 hours the suspect meter read zero. I checked the connections, all good and amps sounded fine. I checked the resistance of both meters in circuit and they both read .8 ohms.
So I ran the amps this afternoon and the meter worked fine for 2.5 hours and it expired, amp sounds fine. After 4 hours the good meter is now reading 52ma on the 60 ma setting when it was running at 64ma as measured and indicated on the meter. So I think I will listen a few more hours then disconnect the meters and measure current directly again than go from there.

[Thermioniclife]

Curiousier  and curiousier, at the five hour mark of listing today the amp with the good meter is now reading 20ma. I sense trouble is at foot and will give me something to do this evening.

[Thermioniclife]

I had to leave the house so I shut the amps off, I don't like to leave things on when I'm out especially since I know the guy that built these amps. I just got back and turned them on and the same issues continue. Going to make dinner then dive in to the problem.

[Paul Birkeland]

What is the DC voltage at pins 1 and 4 on the 4 pin socket?

[Thermioniclife]

Ok with line voltage at 115vac which is quite low for my house even in the summer  p1 to ground 54.6 p2 52,5 across p1 and p4 2.21 vdc, this is the amp I called the bad amp in my first post. On the second amp p1 to ground  53.7 p2 51.5 across p1 and p 4 2.16 vdc

[Paul Birkeland]

OK, the current is being drawn.  Some of these meters stick occasionally and a good really hard knock with your knuckle will wake them up and they'll work well after that. 

[Thermioniclife]

Yeah I gave them the " Technician's tap " from the start with no joy.

[Paul Birkeland]

You can contact replacementparts(at)Bottlehead(dot)com and we can send a replacement meter.

[Thermioniclife]

Turned the amps on this morning and meters work. Thanks for the replacement offer but somehow  I feel that 2 meters that exhibit the same issue is not very confidence inspiring. But I will consider your offer.
I know that I have some .080 dia. test point jacks somewhere in this mess so I whipped up blanking plates for the meters on FPE.
And I may mount the jacks with a 1 ohm resistor to measure current or just blank plates.
These a kind of cheeky.

[Paul Birkeland]

You don't need to be concerned about the meters causing any operational issues in the amp.  Indeed this may be the only product we ever make with meters. 

[Thermioniclife]

I didn't expect that they would but it seems irksome to me. I still mulling. Thanks PB

[debk]

I wish Pete Milett's SiTubes were stil available.  They would be a cool replacement for the meter

[Thermioniclife]

Yeah Deb those were cool! I think they had issues on there own. I haven't thought about them in a long time. I wonder if they are still be manufactured? I'm interested.