already done that there was no change.
Owner said he saw a over voltage light then he powered it off then back on only to produce no audio.
After removing the shorted sot23 PNP I now get audio out of rear channels however none out of front. Also if I refit the PNP I get extreme current draw (13A) then just on/off attemps at building power supply drive
Owner said he saw a over voltage light then he powered it off then back on only to produce no audio.
After removing the shorted sot23 PNP I now get audio out of rear channels however none out of front. Also if I refit the PNP I get extreme current draw (13A) then just on/off attemps at building power supply drive
And no outputs heat up with the pulsing?
Watch the PS FETs so they don't get too hot.
Is the DC on only one channel? 2 channels?
In some of these Orion amps, there is a 10 ohm resistor on the output of each voltage regulator (could be IC regulator or discrete). Confirm that all are within tolerance.
Watch the PS FETs so they don't get too hot.
Is the DC on only one channel? 2 channels?
In some of these Orion amps, there is a 10 ohm resistor on the output of each voltage regulator (could be IC regulator or discrete). Confirm that all are within tolerance.
Power supply does get hot. Not all of them though.
I have felt the outputs get hot when running a subwoofer. If I'm not mistaken (and please correct me if I'm wrong) there is a thing called thermal runaway. What I'd notice when running a subwoofer the outputs would heat up to a certain degree then u would see the amperage start to rapidly increase and the outputs would just get super super hot. I never let it get too bad as I'd shut it down. It's My understanding that this is normal and called thermal runaway and is a result of no heat sink.
No outputs get hot unless u load up the channel
I'll check all the resistors near the volatge regulators. Do you mean the LMs that clamp to the heat sink?
I have felt the outputs get hot when running a subwoofer. If I'm not mistaken (and please correct me if I'm wrong) there is a thing called thermal runaway. What I'd notice when running a subwoofer the outputs would heat up to a certain degree then u would see the amperage start to rapidly increase and the outputs would just get super super hot. I never let it get too bad as I'd shut it down. It's My understanding that this is normal and called thermal runaway and is a result of no heat sink.
No outputs get hot unless u load up the channel
I'll check all the resistors near the volatge regulators. Do you mean the LMs that clamp to the heat sink?
For most all class AB amplifiers, there is a bias compensation transistor that's thermally mated to the outputs via the heatsink. The bias transistor counteracts the tendency for the outputs to pass more current when hot (when at their threshold). When off of the heatsink, the bias transistor can't track (thermally) the outputs so it loses its ability to compensate and the outputs avalanche (runaway).
You stated that you now see ±rail voltage. Why weren't you seeing it earlier? What changed?
You stated that you now see ±rail voltage. Why weren't you seeing it earlier? What changed?
You asked about biasing earlier. It's true that you have to reset biasing after a repair where you replace transistors but it's also possible that someone went into the amp and tried to adjust them to get the amp to work. It's also possible for the bias to drift over time. If none of your outputs are heating up, I doubt the bias is the problem. Just answering the question.
Does this amp have isolated power supplies? Resistance between secondary center-taps?
You stated that 'not all' of the PS FETs heat up. How is the heating gouped? By transformer? By one bank on one transformer? Or random heating?
Is the rail voltage different with and without Q713?
Does this amp have isolated power supplies? Resistance between secondary center-taps?
You stated that 'not all' of the PS FETs heat up. How is the heating gouped? By transformer? By one bank on one transformer? Or random heating?
Is the rail voltage different with and without Q713?
Rail remains the same regardless of PNP in or out.
With Q713 fitted and it initially draws upwards of 13A. Once it settles down and just pulsates only these 2 groups on each side are getting warm. (Circled in photo) others remain stone cold.
They do get very hot on the initial start up when it's drawing 13A.
I'll get that resistance reading for you once I google what the centre tap is on the secondary. Just to be sure I give you an accurate reading
With Q713 fitted and it initially draws upwards of 13A. Once it settles down and just pulsates only these 2 groups on each side are getting warm. (Circled in photo) others remain stone cold.
They do get very hot on the initial start up when it's drawing 13A.
I'll get that resistance reading for you once I google what the centre tap is on the secondary. Just to be sure I give you an accurate reading
Without q713 in circut all the power supply mosfets get the exact same signal on all legs.
With q713 in circut it's almost impossible to see as it just winds up and down probably once per second so its basicly impossible to see.(looking for signal on the PS fets)
Yes every single thing in regards to plus or minus volatge moves with the noise of the transformers.
If u leave it with no power for any decent period of time, then when you go to power it up (q713 in circut) it will not draw excessive current for about 25 seconds (draws about 2A) then goes up to 13A then the transformer noise and palse will be more rapid and it will then draw less current. (Doen to 0.10-1.3A)
I just got word that this amp did indeed see over 16V. Not just the light.
Would it be wise to replace the UC3526? I don't have any on hand but can order it I'd assume.
Just seems as soon as q713 goes in it causes havoc and q713 is connected to pin 17 of the UC. (Thrugh a capacitor)
With q713 in circut it's almost impossible to see as it just winds up and down probably once per second so its basicly impossible to see.(looking for signal on the PS fets)
Yes every single thing in regards to plus or minus volatge moves with the noise of the transformers.
If u leave it with no power for any decent period of time, then when you go to power it up (q713 in circut) it will not draw excessive current for about 25 seconds (draws about 2A) then goes up to 13A then the transformer noise and palse will be more rapid and it will then draw less current. (Doen to 0.10-1.3A)
I just got word that this amp did indeed see over 16V. Not just the light.
Would it be wise to replace the UC3526? I don't have any on hand but can order it I'd assume.
Just seems as soon as q713 goes in it causes havoc and q713 is connected to pin 17 of the UC. (Thrugh a capacitor)