I love the 5e3. Just not mine! Please help.

[JohnRose81]

Digital Multimeter Readings:

Tubes Starting with the 12AY7 and moving to the 5Y3

12AY7:
1: 148
2: 0
3: 2.3
4: 0
5: 0
6: 145
7: 0
8: 2.3
9: 0

12AX7:
1: 189
2: 2
3: 1.5
4: 0
5: 0
6: 234
7: 19
8: 53
9: 1

6V6:
1: X
2: 0
3: 420
4: 383
5: 25
6: 25
7: 0
8: 23

6V6:
1: X
2: 0
3: 419
4: 383
5: 120
6: 117
7: 0
8: 23

5Y3:
1: X
2: 428
3: X
4: 0
5: X
6: 0
7: X
8: 428

Filter Caps Starting with the one CLOSEST to the Power Supply

F1: 425
F2: 386
F3: 285

Fuse: 75 AC
Light: Top 3.3 AC Bottom 3.5 AC
Black and White Power Supply Wires: 122 AC

[g1]

Thanks Dave, makes perfect sense!
I would not recommend trying to measure more than 300V with this meter for safety reasons.

edit: seems there was another thread with some weird readings and the same meter was being used.

[Dave H]

Well, as there is no 300 scale on that meter, it makes sense that the 300V range doesn't work right .

I wondered why it would have a 250V and a 300V scale. They are too close together. The next logical scale after 250V is 500V. I think that is what the '300V' scale really is. The readings make sense if the '300V' scale is thought of as 500V full scale, 120V will then read 120 on both the 250V and ’300V’ scales. The meter is only rated for an input of 300V max so they have called the 500V scale '300V' for ‘elf and safety’ reasons, wonderful!

[g1]

Well, as there is no 300 scale on that meter, it makes sense that the 300V range doesn't work right .
Sounds like all the weird readings were the meter though, so that is good news.
When you get the other meter and can get proper readings, things will progress.
It is normal for the voltage on the filter caps to go up when the other tubes are removed.

[JohnRose81]

Also, if I have just the rectifier tube in, my filter caps show a much higher reading. Also, my normal channel volume pot is scratchy and cuts in and out I'm noticing. I've only been using the bright channel. Never thought about it.

[JohnRose81]

Hey hey. So I bought a digital reader. Screen is blow fun. Too late to return it so I'll do that tomorrow. I did get a couple readings like the filter caps are like 420 for the first one.

I got to your two wires and it was like 120. I can't remember. But I rechecked with the analog one and it read 60 if I was on the 300 setting and it read 120 of I was on the 250 setting. My analog is a m1015b if you want a screen shot of what I'm talking about.

[g1]

I'm unsure by your final question. How would I measure that. The black goes to the fuse and the white goes to the on/off switch. Are you wanting an AC reading of those two wires?

Looking for the AC voltage between those 2. So one probe to the black, other probe to the white.

[nashvillebill]

I see no reason why you shouldn't use NOS tubes there. Lots of folks run old 6V6's in their amps. In fact, when you get loud popping noises from touching preamp tubes, that is a good sign that there isn't a major problem with the power amp section (if there was, you wouldn't hear the pops).

There could be an argument made that it'd be better to use cheap 6V6's when debugging the amp, so as not to potentially expose good expensive tubes to a fault situation, but if the power amp section of the amp is working (and it appears to be) then the NOS tubes are fine, IMO.

[JohnRose81]

Yes, sadly I couldn't get to Home Depot for a new multimeter. As soon as I get home around 5.30 EST I will recheck using the 2.5 and 10 volt ranges for those 2 pins on the pre-amp tubes.

The green wire of the AC cord is attached to the chassis. I bolted it down.

I'm unsure by your final question. How would I measure that. The black goes to the fuse and the white goes to the on/off switch. Are you wanting an AC reading of those two wires?

Also, I'm using NOS tubes for my 6V6's. Old GE tubes. They tested fine, but I'm seeing that I shouldn't use NOS tubes there. If so, I can replace them if need be.

[g1]

I take it that you are still using the same meter. For measuring the DC at pins 3 and 8 of the preamp tubes you need to switch to the 2.5 or 10 volt ranges.
As to the 70V at the fuse, is the green wire of the AC cord connected to the chassis? What is the AC measurement from the white to the black of the AC cord?

[JohnRose81]

Maybe new power tubes are needed...

[JohnRose81]

I don't know the names of the tubes but I started right to left calling the 12ay7 v1 and v5 is the 5y3
F1 is the filter cap closest to the power supply and f3 is the on on the far right.


V1 1:75 2:0 3:0 4:0 5:0 6:75 7:0 noise 8:0 9:0
V2 1:100 2:0 3:0 4:0 5:0 6:125 7:5 8:25 9:0
V3 2:0 3:210 4:190 5:0 6:0 7:0 8:10
V4 2:0 3:210 4:190 5:0 6:0 7:0 8:10
V5 2:210 4:0 6:0 8:210
F1 210
F2 190
F3 145
Fuse top post dc 0 ac 70
Fuse bottom post dc 0 ac 7
Light top post 0 for ac and dc
Light lower post 0 for ac and dc

Ac value on 12ay7 is 155 and ac value on 12ax7 is over 250. I can only go to 250

[eschertron]

So the multimeter is spot on. Put all the tubes in. Plugged the speaker up. Touched the 6 pin on all the tubes except the rectifier tube. The 6v6's registered zero. The preamp tubes popped really loud when I touched them. Once the ax7 read 120. But they just pop and make loud noises and read zero. Cold solder? I re soldered the wires back on the pins. No avail. Would it be the soldering of those wires on the fiberboard? I'll try. Any suggestions?

I think g-one wants you to get readings as per the pins you read in post number six, not necessarily on pin 6 of each tube. Having said that, pin 6 of the preamp tubes is a plate, so it is connected to the grid of the following tube. The popping sound is a good indication that signal is getting through!
Can you AC versus DC volts on your meter? Selecting AC with no signal will give you zero on the pin 6 of the preamp tubes. With a test signal applied to the amp, AC on pin 6 would be a valuable number to have.

[JohnRose81]

So the multimeter is spot on. Put all the tubes in. Plugged the speaker up. Touched the 6 pin on all the tubes except the rectifier tube. The 6v6's registered zero. The preamp tubes popped really loud when I touched them. Once the ax7 read 120. But they just pop and make loud noises and read zero. Cold solder? I re soldered the wires back on the pins. No avail. Would it be the soldering of those wires on the fiberboard? I'll try. Any suggestions?

[g1]

Keep speaker attached at all times. Reread voltages from post #6 with tubes in.
No point doing anything until you verify your meter.
You can take it into a room where you know the outlets are working properly, check what the AC volts reading is at the outlet, does the meter read 120V? If you get a good 120V reading, the meter is not the problem.