Red lead after resistor and black lead on input ground connector of the transformer..
ok now you reporting something i wasn't even aware of.i thought you where still attempting to find the fault with the original components still in place and it seems you can't take the time to accurately report your findings not impossible to resolve but your making it real hard!
You're right, i am always too impatient with electronics... On the other hand, i feel so helpless right now. It's days i'm troubling on this circuit and i really would love to finally fix it, you know. Still have to learn a lot about it, not only by a strictly engineerical point of view, i guess.
well let's back up a step unplug that transformer winding set your meter to AC volts and tell me what you read at the plug?
Well, learning the language is part of learning.
Voltage across a resistor (atras in espanol) is from one end of the resistor to the other end. not from one end of the resistor to ground
The " voltage" without adjective means usually DC voltage from the point discuessed, to the center tap of the transformer, which the diagram says is ground. Which should be the same same voltage as the speaker negative terminal.
So if the two ends of the protection resistor have the same voltage to gnd, the V1 - V2 = zero, which by ohms law, says you have no current across the resistor. (I=V/R) where I is current.
Voltage across a resistor (atras in espanol) is from one end of the resistor to the other end. not from one end of the resistor to ground
The " voltage" without adjective means usually DC voltage from the point discuessed, to the center tap of the transformer, which the diagram says is ground. Which should be the same same voltage as the speaker negative terminal.
So if the two ends of the protection resistor have the same voltage to gnd, the V1 - V2 = zero, which by ohms law, says you have no current across the resistor. (I=V/R) where I is current.
I see! But then i would have a continuity between central tap of any transformer wiring coming out (the 3 ac "to be filtered" rails) and negative terminal of speakers, right? And negative terminal of speakers should have continuity with the circuit ground which is screwed to the heatsink, right?
Well, guys... The center tap of the transformer of the rail we are investing, its ground, has NO continuity with the negative terminal of spekers, therefore NO continuity with the ground connector that goes to the pre board and no continuity with the "general ground" screwed to the heatsink.. Isn't it a clue?
'Cause being at the very same voltage means automatically having continuity, right?
Well, guys... The center tap of the transformer of the rail we are investing, its ground, has NO continuity with the negative terminal of spekers, therefore NO continuity with the ground connector that goes to the pre board and no continuity with the "general ground" screwed to the heatsink.. Isn't it a clue?
'Cause being at the very same voltage means automatically having continuity, right?
ok your doing it again ...making it hard
16.5 v... but what ac or dc (if you don't specify it it can lead to assumptions) and is that "across" the full winding? what is each half with respect to the center tap of that winding (it is a bipolar supply isn't it!)
16.5 v... but what ac or dc (if you don't specify it it can lead to assumptions) and is that "across" the full winding? what is each half with respect to the center tap of that winding (it is a bipolar supply isn't it!)
Ok, 16.5 Vac. I don't know how to say it, i have 3 cables, the ground in the middle and two external wires. On each of these two wires, with the black lead of the meter on ground, i have 16.5 Vac. I suppose that means is bipolar!
well if the heatsink is grounded i hope that in your hurry up approach you didn't forget things like mica washers/insulators on any of the semi's you "replaced" ask indianajo about what kind of problems that can make for you!
and please don't start jumpering grounds please inspect the board for cracks broken traces and any potential points that can go open like header pins even things like the crimps inside a multipin connector can go bad.
and please don't start jumpering grounds please inspect the board for cracks broken traces and any potential points that can go open like header pins even things like the crimps inside a multipin connector can go bad.
after re reading through the thread you say that you didn't replace the ceramic's in the supply section i wonder what you'd get with those out of circuit.
I putted the insulators at their place, i don't have any of that white kinda silicon.. There still is something on the insulator, though. But i'm talking obviously of the out transistor, the thermal sensor and the lm1875.. No component if this rail is heatsinked.. But good you remind me how important it is (maybe more long term?).
I could try taking the ceramics off, i'll do it right now, but we stated the problem is before them, right?
Question: should i have always continuity between all grounds? Like the speaker negative terminal, the transformer ground, the heatsink etc...
I could try taking the ceramics off, i'll do it right now, but we stated the problem is before them, right?
Question: should i have always continuity between all grounds? Like the speaker negative terminal, the transformer ground, the heatsink etc...
Last edited:
What would happen if i would tell you that R23 measures 586 Kohm and R22 Measures OL (open lead)?
And if i would tell you that i desoldered them and checked off the board, with the same result??
I mean ACROSS the resistor, to be clear...
And if i would tell you that i desoldered them and checked off the board, with the same result??
I mean ACROSS the resistor, to be clear...
hey i hope i'm not hasty but i think you found it!
what would happen ? i'd say you owe me a bottle of scotch
but we're not out of the woods yet!
what would happen ? i'd say you owe me a bottle of scotch
but we're not out of the woods yet!
Last edited:
hey i hope i'm not hasty but i think you found it!
what would happen ? i'd say you owe me a bottle of scotch
Only tequila for you ! 😀😀
I think i owe you and indianajo much more and i think i know what to do at the end of this adventure.. You'll see.. 😉
Anyway, come on.. How possible is this?? Have you ever encountered a couple of burned carbon resistors?
yup some are specifically designed to be like fuses look up PICO fuses.
"much too learn, you have, young Jedi"
"much too learn, you have, young Jedi"
Oh yeah.. Absolutely... Too bad i didn't ordered them. I should find something out from the bunch of electronic waste i got here. Looks a very standard size resistor.. Is that allright for you?
- Status
- Not open for further replies.