You don't need a heat gun to remove/replace those SMD transistors.
Why are you trying to run the amp with Q424/25 out of the circuit?
Why are you trying to run the amp with Q424/25 out of the circuit?
removed with this
i dont know why, at least it stays on with out them.
i believe amp melts if i keep it on more than 3seconds with Q´s on.
Been lately more Donald Duck than Gladstone Gander
Amp melts?
To remove the SMD transistors, bridge the adjacent terminals with solder, heat and lift the transistor to about 45°. Desolder with braid then heat the last terminal, pushing the transistor off the pad or lifting it with tweezers.
To remove the SMD transistors, bridge the adjacent terminals with solder, heat and lift the transistor to about 45°. Desolder with braid then heat the last terminal, pushing the transistor off the pad or lifting it with tweezers.
Yes it started to take lots of current with Q's on.
My amp meter goes 50amps and it goes over that
My amp meter goes 50amps and it goes over that
No, it was set quite low. Tried with factory transistors and its same thing.
If i put q's on i have to maybe remove output fet's to make measurements
If i put q's on i have to maybe remove output fet's to make measurements
yes, removing Q401 changes things up. speaker output is pulsating -82Volts now.
But noticed untouched channel hasn´t bias without Q425/Q424, now there is 4mV. (set it up earlier to 2mV, wont bother it at this point)
Q401 is located in that area, being right handed with heatgun i think i would not heatet that much as most heat went much opposite direction.
well, new Q401´s then? R401 and R402 are in specs.
i made earlier this transistor comparer, there is places TO92 and SOT23.
with TO92 i reduced DC on one amp 50% changing "matched" transistors.
But with SOT23 that chinese case being so flimsy its really hard to get readings
But noticed untouched channel hasn´t bias without Q425/Q424, now there is 4mV. (set it up earlier to 2mV, wont bother it at this point)
Q401 is located in that area, being right handed with heatgun i think i would not heatet that much as most heat went much opposite direction.
well, new Q401´s then? R401 and R402 are in specs.
i made earlier this transistor comparer, there is places TO92 and SOT23.
with TO92 i reduced DC on one amp 50% changing "matched" transistors.
But with SOT23 that chinese case being so flimsy its really hard to get readings
The problem is that some transistor in the circuit is causing the low-side FETs to drive fully on. When the amp powers up and Q401 switches on, the amp tries to compensate which causes the high current draw. Re-check ALL transistors in that channel.
maybe touch all thru with cold and hot item watchin output voltage at same time?
output voltage should be 0 with that q401 off board?
Thanks again Perry
output voltage should be 0 with that q401 off board?
Thanks again Perry
I don't think the problem will be temperature sensitive.
With Q401 removed, the circuit is the same as when the amp is in its initial mute delay. Yes, 0v at the output.
With Q401 removed, the circuit is the same as when the amp is in its initial mute delay. Yes, 0v at the output.
Q408 and Q407 needs to be changed
Q403 and Q404 aint good pair either
MPSA56 and MPSA06, id like to get couple of those so i can choose best pair.
US newark has them but same group farnell doesn´t, my local store can get parts from farnell fast.
any recommendation replacing those?
Q403 and Q404 aint good pair either
MPSA56 and MPSA06, id like to get couple of those so i can choose best pair.
US newark has them but same group farnell doesn´t, my local store can get parts from farnell fast.
any recommendation replacing those?
When amp was working i noticed these run very hot. (group of TO92´s above bypass text)
So just thinking if item with larger case could be used, atleast stick those TO92´s into heatsink ?
But yeah, i can get these from mouser
I don't know if it's normal. If no one else can give you a definitive answer, get the other channel working and see if the corresponding transistors in the other channel get equally as hot.
Those transistors above the bypass switch do indeed run hot on almost every Rockford amp I have seen. Do you have a temp gun? How hot are they getting?
I havent got that, guessing 60-70celsius.
Ordered TS100 soldering iron cause i rather use heatgun with these smd's rather than my cheap iron
Ordered TS100 soldering iron cause i rather use heatgun with these smd's rather than my cheap iron
got little time to mess around with this amp again, factory Q424 and Q425 is actually one of the best pair i´ve measure with my device so throw them in again, and they are rather more powerful than these new what i have 100pc.
if i put new Q424-425 i should change them to left channel too?
Is it so that high´ish DC could come from even from that Q403 which aint pair with Q404.
When i get this channel good again and start to work with left channel im gonna check those TO92 first, if theyre ok im head up Q303-304.
if i put new Q424-425 i should change them to left channel too?
Is it so that high´ish DC could come from even from that Q403 which aint pair with Q404.
When i get this channel good again and start to work with left channel im gonna check those TO92 first, if theyre ok im head up Q303-304.
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hours of work and new parts, +42V rail stays on speaker output.
wonder if i broke the board with heatgun
wonder if i broke the board with heatgun
Dear sir
do you have the schematic for this amplifier? or you are just guessing the way to fix this amplifier?
do you have the schematic for this amplifier? or you are just guessing the way to fix this amplifier?
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