dear people.
first of all I ask sorry for my English...
I hope someone help me, I read along this trehad, but I not found what solve ( or try to do ...) my problem.
I buyed for some buck the 1.5t.
Is really damaged, but whit a lot of patient and much more time, time after time I soved the problem the are front to me.
Started whit the ampli board now I'm stocked whit the regulator board.
I',m not have the original transformer but a couple of toroidal (from the beginning are inside and seems installed from a qualified person).
BDW...
I discoverd the Triac and the oc1 fused.
the diac are ok, the diode are ok, the resistor ok.
Changed triac and oc1,
but I have this problem : i read that the diac have to fire at 40 volts, and so the triac have to open from that voltage, but this not happen.
Infact , using a variac, at 25 volts the diac fires, and the same do the triac, and the trnasformer start to work.
And, also, more volts give to the ampli, more volts going to the trnasofrmer, seems the regulator no regulator nothing
Do you have idea what is the firing voltage at the triac ?
and (in the manual are not present) what is the exact model of the oc1 ?
tks and regards from Italy!-
Hi guys, sorry for coughing up such an old thread. I am also an amptech from the Netherlands and wonder if speakertech has been successful in repairing the PM1.2. If not, it is probably sold and now in my workshop. Complaint: broken fuse and loud fan. The fan isn't an issue, but powering this thing is definitely a pain. The solution is simple if you take a closer look at the matter. The transformer is simply nothing more than a transformer with a lower primary voltage than usual, depending on the feedback. The triac ensures that the 230V~ is reduced to an acceptable current. There was an interruption in the feedback, so that the transformer had to deal with the full load. I tackled this by using a series lamp which leaves the fuse intact. Then it's a matter of measuring. It turned out that the wiring was inserted through a hole in the board, folded over and soldered into the PCB. This gives good strain relief but puts a lot of stress on the weld. This weld was therefore cracked. The optocoupler had also reached its maximum flight hours, so also replaced it just to be sure. Problem solved.
Hi cluseau,
These are special power supplies. I'm glad you got it working. There is a proceedure for soft starting these amps on the bench, and using a series lamp is not it. I guess it worked for you though.
It isn't simply a transformer with too few a turns ratio for full ine voltage, it is designed to deal with the chopped waveform from the triac. The filter capacotors also have to deal with this waveform. The PM series do use a fan, don't replace it with a kit that uses a sensor, just put the same type of fan in. Often if you lubricate the bearings the fan will be okay unless it has run for a long time dry.
The internal communtating power supply is set for bas or full range music. If you hit them with sine waves at higher frequencies, or high power mid or high frequency use these commutators will "lock up" which will overheat the amplifier until the signal is removed or lowered in level.
Yes, like any switch mode power supply, if the AC line voltage falls they will draw higher current to maintain the internal supply voltages. They are designed to be used with solid AC supplies. Any other high power amplifier will drop internal supplies and deliver less power and possilbly performance. Anyway, a high tech amplifier designed to perform well under reasonable conditions. The power supply itself incorporates both feedback and also great fault protection.
I was Canadian factory warranty for Carver and understand them very, very well.
-Chris
These are special power supplies. I'm glad you got it working. There is a proceedure for soft starting these amps on the bench, and using a series lamp is not it. I guess it worked for you though.
It isn't simply a transformer with too few a turns ratio for full ine voltage, it is designed to deal with the chopped waveform from the triac. The filter capacotors also have to deal with this waveform. The PM series do use a fan, don't replace it with a kit that uses a sensor, just put the same type of fan in. Often if you lubricate the bearings the fan will be okay unless it has run for a long time dry.
The internal communtating power supply is set for bas or full range music. If you hit them with sine waves at higher frequencies, or high power mid or high frequency use these commutators will "lock up" which will overheat the amplifier until the signal is removed or lowered in level.
Yes, like any switch mode power supply, if the AC line voltage falls they will draw higher current to maintain the internal supply voltages. They are designed to be used with solid AC supplies. Any other high power amplifier will drop internal supplies and deliver less power and possilbly performance. Anyway, a high tech amplifier designed to perform well under reasonable conditions. The power supply itself incorporates both feedback and also great fault protection.
I was Canadian factory warranty for Carver and understand them very, very well.
-Chris
Thanks for your feedback Chris. I am aware that a lamp is not the right way but my variac has died in action . The lamp then gave me some protection to make short-term measurements. In my case, only the feedback was intermittent. The reason I want to post this here is that several amps can have this problem. The wire is in a very tight bend intended for strain relief but over time the wire wants to stretch which puts force on the weld. Kind of common error.
I assume that the transformer (inductive load) in cooperation with the capacitors form a resonator to handle the triac circuit. Someone had been messing around there too. C4 was made of two piggybacked 100nF caps. The original value should be 470nF.
The fan was almost stuck. Lubricating the bearings helped a bit but was unreliable. An 80x80 fan fits exactly and is much quieter. Running on 15V= it blows frienly but when the thermoswitch switches on, it's a hurricane.
Nice design but definitely important to read the description, fortunately I have the manual.
regards
Frans
. The lamp then gave me some protection to make short-term measurements. In my case, only the feedback was intermittent. The reason I want to post this here is that several amps can have this problem. The wire is in a very tight bend intended for strain relief but over time the wire wants to stretch which puts force on the weld. Kind of common error.I assume that the transformer (inductive load) in cooperation with the capacitors form a resonator to handle the triac circuit. Someone had been messing around there too. C4 was made of two piggybacked 100nF caps. The original value should be 470nF.
The fan was almost stuck. Lubricating the bearings helped a bit but was unreliable. An 80x80 fan fits exactly and is much quieter. Running on 15V= it blows frienly but when the thermoswitch switches on, it's a hurricane.
Nice design but definitely important to read the description, fortunately I have the manual.
regards
Frans
Hi Frans,
Sorry to hear you lost your variac. It is one of the most essential pieces of equipment for working on amplifiers (and other things).
I haven't had any problems with the connections you are seeing. C4 just goes across the line to reduce spikes, the voltage rating would be higher for your market of course.
For various Carver amplifiers I use the variac, and different DC power supplies depending on the model and problem area. The biggest problem with forums and that darned "light bulb" is that people use them without understanding the possible effects on the circuit they are powering up. If you have a lot of experience it can be an expedient, but I have tried and no longer use a light bulb. I need to have a defined input voltage and read the current. Otherwise it is easy to misdiagnose a problem. Certainly I can't have the input voltage varying as I troubleshoot an issue!
Your fan solution sounds good. That's something I would do, I found some fan motors and always prefer to restore equipment to original configuration unless there is a good reason to change things up. Sounds like that fan was run way past the time it needed service. Why don't people fix things when they need it? Equipment is always run until it no longer can be used, then they are upset it costs more.
The manual is actually pretty good at explaining how it works. We still had to close warranty stations because they either can't read or refused to understand what they were fixing. That was the biggest issue, most techs did not understand how these worked, but dove right in anyway. These days the situation is worse as you can see. There was a very good reason Carver restricted service on these and did not release service information. Normally I have a problem with that, but sometimes with truly advanced ideas and design they are forced to do this. I can't tell you how many mag coils we sold (no returns) after warning the buyer that this part was not the problem. Then getting complaints that the new part was defective!
These days I am so tired of what hacks do to equipment! I thought it was as bad as it could get years ago, but the situation continues to deteriorate! I'm so glad I'll retire in a couple years I think.
-Chris
Sorry to hear you lost your variac. It is one of the most essential pieces of equipment for working on amplifiers (and other things).
I haven't had any problems with the connections you are seeing. C4 just goes across the line to reduce spikes, the voltage rating would be higher for your market of course.
For various Carver amplifiers I use the variac, and different DC power supplies depending on the model and problem area. The biggest problem with forums and that darned "light bulb" is that people use them without understanding the possible effects on the circuit they are powering up. If you have a lot of experience it can be an expedient, but I have tried and no longer use a light bulb. I need to have a defined input voltage and read the current. Otherwise it is easy to misdiagnose a problem. Certainly I can't have the input voltage varying as I troubleshoot an issue!
Your fan solution sounds good. That's something I would do, I found some fan motors and always prefer to restore equipment to original configuration unless there is a good reason to change things up. Sounds like that fan was run way past the time it needed service. Why don't people fix things when they need it? Equipment is always run until it no longer can be used, then they are upset it costs more.
The manual is actually pretty good at explaining how it works. We still had to close warranty stations because they either can't read or refused to understand what they were fixing. That was the biggest issue, most techs did not understand how these worked, but dove right in anyway. These days the situation is worse as you can see. There was a very good reason Carver restricted service on these and did not release service information. Normally I have a problem with that, but sometimes with truly advanced ideas and design they are forced to do this. I can't tell you how many mag coils we sold (no returns) after warning the buyer that this part was not the problem. Then getting complaints that the new part was defective!
These days I am so tired of what hacks do to equipment! I thought it was as bad as it could get years ago, but the situation continues to deteriorate! I'm so glad I'll retire in a couple years I think.
-Chris