Bad amp grounding??

[nosaj]

Problem with the meter or probes if measurements are not the same day to day, no?
nosaj

[Chuck H]

Problem with the meter or probes if measurements are not the same day to day, no?
nosaj

I noticed that as well.

[DrGonz78]

How this?

With a good C12 connected across R24, the reading should be 1.5k just as without C12.
Maybe you mean measuring only C12?

You know I got so confused by the flow of this thread that I started confusing myself too. thanks for reminding me again Helmholtz.

Sea Chief I understand completely when you say you get confused with all these circuits. You got the amp working so that is great. Now time to look into that meter and make sure it’s working correctly. Last thing you want is a meter that gives answers randomly like a magic 8 ball.

[Sea Chief]

Problem with the meter or probes if measurements are not the same day to day, no?
nosaj

Hi nosaj,

I expected this reply tbh. No, I wouldn't do any test you guys are kindy giving time to suggest doing, unless the probes are fixed well (mini tiny croc clips on each probe so they stay put), checked again beforehand, the plugs pushed in & checked beforehand, a continnuity check beforehand making sure DMM ok.. then I do a test.

I Couldn't be more meticulous tbh, confident of my thoroughness, & of the DMM too, plus Ive never such a discrepency doing same test next day too.. never.

It has to be a different reading because of only one thing: the problem tube was actually, for a day or so, taken from its original v1 position.. & put into v5 position. And a reading to R24 taken. Then, the next day, when I likely was trying out another tube in v5, this time a good one ( but the noise remained, because id put problem tube Z back into V1, not realising it was bad at this point) so a different good tube in v5 now.. I take a reading to R24.

Different readings. This can only be the reason. Not me or my equipment.

The bad PI tube was the cause of this problem. Removing v5 & the noise stopping gave a false impression the cause was therefore definitively isolated to the input area. This is what I believe, from the evidence in front of me. But I am very happy to be challenged on this notion, because I have a fraction of any if you guys' experience.

SC

[DrGonz78]

Hi nosaj,

I expected this reply tbh. No, I wouldn't do any test you guys are kindy giving time to suggest doing, unless the probes are fixed well (mini tiny croc clips on each probe so they stay put), checked again beforehand, the plugs pushed in & checked beforehand, a continnuity check beforehand making sure DMM ok.. then I do a test.

I Couldn't be more meticulous tbh, confident of my thoroughness, & of the DMM too, plus Ive never such a discrepency doing same test next day too.. never.

It has to be a different reading because of only one thing: the problem tube was actually, for a day or so, taken from its original v1 position.. & put into v5 position. And a reading to R24 taken. Then, the next day, when I likely was trying out another tube in v5, this time a good one ( but the noise remained, because id put problem tube Z back into V1, not realising it was bad at this point) so a different good tube in v5 now.. I take a reading to R24.

Different readings. This can only be the reason. Not me or my equipment.

The bad PI tube was the cause of this problem. Removing v5 & the noise stopping gave a false impression the cause was therefore definitively isolated to the input area. This is what I believe, from the evidence in front of me. But I am very happy to be challenged on this notion, because I have a fraction of any if you guys' experience.

SC

So the only way to truly know is to test the hypothesis. To not test the hypothesis is merely a guess. Maybe your right but you won’t know it until you prove it. That is troubleshooting in a nutshell.

[Sea Chief]

So the only way to truly know is to test the hypothesis. To not test the hypothesis is merely a guess. Maybe your right but you won’t know it until you prove it. That is troubleshooting in a nutshell.

Absolutely. And I know this tube is bad.. but I'm tempting fate (with my flippin luck) d*cking about with it further, to test the hypothesis, when its fine again right now "so just stick there already, don't fkn touch it you tw*t" is what sensible diddy leprechaun on my left shoulder's hollerin at me! he's a rude little sod today.

Thx SC

[nosaj]

Absolutely. And I know this tube is bad.. but I'm tempting fate (with my flippin luck) d*cking about with it further, to test the hypothesis, when its fine again right now "so just stick there already, don't fkn touch it you tw*t" is what sensible diddy leprechaun on my left shoulder's hollerin at me! he's a rude little sod today.

Thx SC

Then mark the damn thing or throw it away so we don't have another 4 page thread on it since post #2 stated what to do and it took 2 threads and and 4 pages on this one for your to finally get there.

nosaj

[nosaj]

Before you go off on a tangent or anything ... The problems I have listed recently in this thread are problems I myself have firsthand experienced. chasing my tail with dodgy probes, not listening to what was conveyed to me, thinking I was right and being thorough when in fact i didnt understand what was being asked of me, multipage threads(ask JM Fahey hes been through a few with me. I see myself and actions in yours. So before you take umbrage and think I'm picking on you I'm not, just realize you are your own roadblock to this whole thing.

nosaj

[Sea Chief]

Then mark the damn thing or throw it away so we don't have another 4 page thread on it since post #2 stated what to do and it took 2 threads and and 4 pages on this one for your to finally get there.

nosaj

Hi nosaj,

no hang on there. No-one told me to touch v1 (phase inverter, the problem tube). I was only told to undo v5: this is why it took 4 pages buzzing around the input area, & me fluke-finding this rogue tube in v1.. which accounts for the odd resistance measurements one day to the next (coinciding with me swapping v5 & v1 around seemingly a sensible thing to do I thought: & fluke-finding the problem tube purely by chance).

Its no-one's fault this v1 tube was missed, & I don't think you can blame muggins here!

[Helmholtz]

Might have been a tube with an intermittent heater-to-cathode short.

[Intripped]