Ceriatone yeti - no sound

[Wenzelli]

Hey guys, I have a ceriatone yeti that isn’t putting out sound. If you have any suggestions on what to look at to debug please let me know. I’ve got Dc heaters on v1 and v2. Any pin not mentioned is roughly 0, this is with no tubes installed. Further down is with all tubes installed.

No tubes:
Dc voltages
V1
1-438v
6-449
9-6.1v

V2
1-451v
6- 457v
7-451v
8-147v
9-6.1v

V3
1-454v
6-453v
7-21v
8-32.3v
9-0v

V4
3-466v
4-467v
5- -38v
6-468v

V5
3-468v
4-468v
5- -37v
6-468v


Voltages with all tubes installed:
V1
1-147v
3-1.3v
6-189v
8-1.5v
9-6v

V2
1-142v
2- -.02v
3- .88v
6-251v
7-143v
8-143v
9-6.1v


V3
1-203v
2-20v
3-31v
6-185v
7-185v
8-31v


V4
3-444v
4-443.5v
5–38.5v
6-444.5v


V5
3-443v
4-442.5v
5- -37.5v
6-444.5v

[Wenzelli]

Also when probing all tube pins with a chopstick, volume is up but there is no sound whether touching pre or power grid & plate pins.

[zircontweezer]

Seems to be pointing at a bad speaker connection if your probing the plates of the power tubes and no noise. Withe the amp unplugged and caps discharged you can put a 9vdc battery across the output jack and see the cone move on the speaker if the jack, speaker cable and speaker are ok. Could be a bad output transformer but I'd try that test to see what happens. The voltages seem normal. Others may know more.

[Wenzelli]

Seems to be pointing at a bad speaker connection if your probing the plates of the power tubes and no noise. Withe the amp unplugged and caps discharged you can put a 9vdc battery across the output jack and see the cone move on the speaker if the jack, speaker cable and speaker are ok. Could be a bad output transformer but I'd try that test to see what happens. The voltages seem normal. Others may know more.

Hey thanks for the reply. Would I just put the negative lead of the battery to ground and positive to  jack tip where the red wire is on the layout? Or other way around?

[tubeswell]

Would I just put the negative lead of the battery to ground and positive to  jack tip where the red wire is on the layout? Or other way around?

Either way. One way the speaker cone will pop out, the other way, it will pop in.

[PRR]

With output transformer connected, I would not expect a visible motion from a 9V battery. (The OT winding is less than 1 Ohm, a super heavy load for a wee battery.) It may "tic" but not loud.

In general a wall-powered amplifier WILL hum/hiss if you put your ear in the speaker. If not, the speaker is not really connected. Check wiring. Clean contacts.

[Wenzelli]

Hey guys, there was some fairly loud ticking like you mentioned when the battery was across the output jack so I think the output jack is good. Speaker, speaker cord are definitely good as tested with a working amp. Any ideas of what to check next?

Also I feel like getting an oscilloscope to check this kind of stuff out but I’m not sure which one to get that would have a signal generator as well. Does anyone know of any good ones for around $300?

[zircontweezer]

Have you checked the AC heater voltage on the power tubes and ecc83 thats connected to the lamp? You don't have those listed on your voltages.

[Wenzelli]

Have you checked the AC heater voltage on the power tubes and ecc83 thats connected to the lamp? You don't have those listed on your voltages.

Thanks again for your reply
V3 between 4&9, 5&9: 6.17vac
V4 between 2&7: 6.17vac
V5 between 2&7: 6.2vac
Pilot light between pins: 4.2vac

[eggbert]

I would suspect the impedance selector is no good or wired wrong, had this on a Jcm 800, couldn’t get anything out of the amp.  Disconnect it and wire just one secondary tap direct to speaker jack, or your speaker jacks wired wrong or no good.
Good luck

[eggbert]

Also check R and the tip off speaker jacks... are these reversed ?

[tubeswell]

Or it could be your OT is dead. hook up a dummy load and scope the secondary (with a signal at the input)

[sluckey]

Do you have a schematic?

[Wenzelli]

Do you have a schematic?

I don’t. the layout is at the top but it’s a pretty straightforward jcm/2204 style Marshall with some tweaks

[Wenzelli]

Or it could be your OT is dead. hook up a dummy load and scope the secondary (with a signal at the input)

Do you have any low priced oscilloscopes that you’d recommend with a built in signal generator? Or a stand-alone and signal generator? I have yet to get one but would like to get one to fix this.

[sluckey]

I don’t. the layout is at the top but it’s a pretty straightforward jcm/2204 style Marshall with some tweaks

This amp is considerably different from a 2204!

Not gonna find a cheap scope/sig gen combo. Gotta buy separate units. But I believe your problem is wiring error or incorrect component value. Should be able to find with your eyes and a DMM. You are severely handicapped without a schematic. Never understood why Ceriatone doesn't include a schematic. I know they cater to non-tech people but so often these amps end up on forums with lots of tech savy people. But without a schematic, we're just as blind as you, especially since we can't put our hands on the amp. Maybe Nik will send you a schematic.

[Wenzelli]

I don’t. the layout is at the top but it’s a pretty straightforward jcm/2204 style Marshall with some tweaks

This amp is considerably different from a 2204!

Not gonna find a cheap scope/sig gen combo. Gotta buy separate units. But I believe your problem is wiring error or incorrect component value. Should be able to find with your eyes and a DMM. You are severely handicapped without a schematic. Never understood why Ceriatone doesn't include a schematic. I know they cater to non-tech people but so often these amps end up on forums with lots of tech savy people. But without a schematic, we're just as blind as you, especially since we can't put our hands on the amp. Maybe Nik will send you a schematic.

Haha forgive me, you’re right it is pretty out there. I’ve been looking at too many Jose mods. And gotcha with the oscilloscope, just not sure which one to get that would be good. You may be right about a wiring error, when I get back from vacation I will post some pictures and maybe draw a schematic

[PRR]

Funny sound, a 'scope might help.

_NO!_ sound, an AC voltmeter will trace where sound stops.

Don't buy a defibrillator for a hangnail.

[drew]

Don't buy a defibrillator for a hangnail.

Yeah. And something about horses, not zebras. 

[Latole]

Ac voltmeter or 'scope to follow signal path ( sound ) ; first you need to know how to use them .