thank ZM 🙁 for the help.
ok the fuse not burn with no load.
the gnd PSU permanently connected to chassis.
about the k170 transistor, why its burn?
maybe i short the rca?
i don't have potentiometer and i connect cdp direct! problem?
now i don't have spare transistor, i think to bay 2SK246, more chip.
thank for your help, I'm sure that in the end the F5 work fine 🙂
ok the fuse not burn with no load.
the gnd PSU permanently connected to chassis.
about the k170 transistor, why its burn?
maybe i short the rca?
i don't have potentiometer and i connect cdp direct! problem?
now i don't have spare transistor, i think to bay 2SK246, more chip.
thank for your help, I'm sure that in the end the F5 work fine 🙂
read thoroughly powering up/testing procedures for F5
I believe most recent one is written by 6L6
check all resistors , wiring and semiconductors
pull out Jfets ad test them with simple matching jig ( search on forum)
same for mosfets
I believe most recent one is written by 6L6
check all resistors , wiring and semiconductors
pull out Jfets ad test them with simple matching jig ( search on forum)
same for mosfets
hi
i have another channel that work, so i compare all resistor and transistor.
the only different was in the k170 transistor, 0.7v between the leg > normal, but the resistance between the leg is 17k ohm, so its broken.
but whey, the amp work fine for few days !
what can be reason for this transistor fail?
i just don want to buy and burn it again.
thanks
i have another channel that work, so i compare all resistor and transistor.
the only different was in the k170 transistor, 0.7v between the leg > normal, but the resistance between the leg is 17k ohm, so its broken.
but whey, the amp work fine for few days !
what can be reason for this transistor fail?
i just don want to buy and burn it again.
thanks
each transistor is having 3 legs , each one having it's name and role
so , when you wrote 0,7V , you need to tell us between which legs is that measured
as I said ( and it will be easier now , with one channel functional ) - triple-check everything , then proceed
Jfet can be broken from various reasons - maybe you slipped probe when measuring , maybe it's overheated during soldering ( common mistake when doing first projects ) etc.
so , when you wrote 0,7V , you need to tell us between which legs is that measured
as I said ( and it will be easier now , with one channel functional ) - triple-check everything , then proceed
Jfet can be broken from various reasons - maybe you slipped probe when measuring , maybe it's overheated during soldering ( common mistake when doing first projects ) etc.
ok i check again. i don't think it overheat, just plug out the rca from the cdp (no potentiometer->full power from F5) and plug in the rca to pc and then the speaker burn with the 30v dc, smell not good from the speaker.
yess jfet, 0.7 between base -emitter.
yess jfet, 0.7 between base -emitter.
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I hope that , during re-plugging of RCA cables , amp was off and volume on PC was fully down
if not , there is nothing unusual if you blew something
base -emitter ... you probably think gate - source
define how you measured that 0,7V
if not , there is nothing unusual if you blew something
base -emitter ... you probably think gate - source
define how you measured that 0,7V
i re-plug the RCA cables a lot of time during testing the F5.
i unplug the speaker and then plug RCA (sometimes with vol), the amp was always on.
i hope this is the reason for the transistor break.
next time i torn of the F5>vol down> re-plugging of RCA cables.
i unplug the speaker and then plug RCA (sometimes with vol), the amp was always on.
i hope this is the reason for the transistor break.
next time i torn of the F5>vol down> re-plugging of RCA cables.
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