Re: fuse power amp is good I have power on power supply...
Clean all the control pots. i forget the name but there is a spray that u use, then turn knobs back and forth. should cure that problem. that has worked for me cause they only get moved so much so just even dust will sit in there,. good luck.
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John
With AC power off.
Use a meter (on Ohms scale) to check internal fuse for blown (open) fuse.
If you feel qualified & safe with AC Power On.
Check input to internal power supply on AC Scale (Caution when AC is on) for volts in.
Use meter on internal Power Supply for "probably" DC volts leaving internal Power Supply electronics to power the rest of the electronic circuits.
Switch mode power supplies can break down. They stop doing their high frequency switching so they don't convert AC to DC.
If this P/Sup is a separate box or circuit board, inside the unit, then it can have a part number & be replaced.
Good Luck
First is to check to make sure the power supply is putting out enough power.
From your description, it sounds like the classic signal "clipping" situation.
Since I tend to work from experience repairing a wide range of things, and I am not finding any references to your amp, not even in Russian sources, not even a picture, I have to make some assumptions for the moment, but this will help locate the problem.
Solder some test leads to an impedance matching transformer and the other winding to a plug that will fit your good headphones.
With chassis underside exposed, power up the amp, and apply a song you know well to the input. Use the test leads to check the 4558 IC's that are most likely to be found in the preamp stage(s) of the amp. and follow down the audio chain until you reach the power hybrids. If you happen to have the discrete transistors, those are better to work with and much easier to test.
If I am testing an amp in this way, I am listening for a dead spot, or a spot where the signal is very distorted. Being careful not to touch the power buss. Simply putting a test clip on one lead and attaching it to chassis ground is the easiest and fastest way to run through an amp.
if I am checking discrete transistors, I am just checking at the base lead of each one, or the gate if it is a FET until I find a distorted stage.
If you have power hybrid IC's, check at the website of the manufacturer of the IC for data sheets on that chip. Use those as a guide for checking voltages for the hybrid, as well as to help potential shorted components such as a capacitor or a resistor that may have failed.
If I know more details of the chips the amp uses, discrete transistors, or even if it happens to be a tube amp I can be much more specific. Other things to check that are not always apparent- make sure there is a +15 colt supply and a -15 volt supply with respect to chassis ground when dealing with 4558 amp chips.
Probably NOT the transformer as most of these have switching type supplies. A Chauvet unit I have would not light and the problem was the socket for the Halogen bulb. The socket had burned and the contacts were so burned they would not contact the bulb. Worse, you can't even see the problem as the socket is ceramic and has a mica like cover. Replacement of the socket fixed the problem. In the Chauvet unit they had a very cleaver lamp power supply. That threw me off because there was no voltage at the socket... until I put the Oscilloscope on it... then there were tiny spikes. It turns out the supply sends tiny spikes out and IF the lamp is there and contacts are good, the supply senses the load and the feedback starts driving the supply to full output. I wasn't able to see the burned contact until I uncapped the socket. Just maybe you have a similar problem. These 250 watt Halogens with the tiny pins carring 11 amps just are ******* the contacts in the sockets.
if it does not power up, then it means its having a power problem. it might have worked fine in the past, but that's electronics for you. Power surge, irregular power supply, excess power supply, etc can affect the unit thereby not making it to power on.
This unit must have a power supply board in it where power enters from the mains. A capacitor, fuse, diode, etc may have been defective on the power board and maybe that's why its not making the unit turn on. There might also be some disconnection or something, inside the unit which is not making it to power on.
To actually find out what's wrong, you need to disassemble the unit with a screw driver and check what's wrong. You will be needing a meter in order to test the components on the power board, once you detect any bad component, you can make necessary replacement at any electronics accessories store withing our vicinity. This is the only way by which you can detect the problem.
Of course, testing the power board with a meter will require someone that has the ability. So it you can't, then you might be needing the help of a repairman or you can call a friend that has the ability to help you out.
The power supply is blown. Argentina is 220V I believe. I have never seen a power supply schematic for this however being that it is low power it is a linear supply not switching. Either the rectifier diodes are blown out or possibly the output capacitors are blow due to approx double voltage. If you try this yourself be careful otherwise get a new amp. Good Luck
Your amplifier is a solid-state rectified tube amplifier. This means that a tube is NOT used for the power supply. Why is this significant? Because most of the time you have the problem you are describing, it is because of the tube rectifier.
Since this amp does not have a tube rectifier, the problem is likely one or more of the tubes. I have seen in 95% of the amps I repaired that the tubes were the cause, and since the amp is so new, I would suspect tubes first.
Now the hard part: which tube? Without a tube tester, you will have to use the 'firewall' technique. You will need to get a bunch of replacement fuses, as you might go through a few untill you find the problem. Radio Shack is a great place for fuses (make sure they are SLOW BLOW type).
The problem is almost guarenteed to be the power tubes: they are a big failure mode in tube amps (the preamp tubes are not as likely the problem).
This is what I do at a customer site without a tube tester:
(1) Have either a KNOWN TO BE GOOD REPLACEMENT SET OF TUBES or a NEW SET OF TUBES.
(2) Have plenty of fuses.
(3) Start with power tubes: they cause most of these problems. Replace burned out fuse.
(4) Replace all 2 (or 4 in your case) with the good tubes.
(5) Turn on amp and play on it (30 minutes at various volumes and settings). Turn it on and off many times using the on/off procedure your amp requires (like using the standby switch on some models).
* if the amp plays and works, likely you had a bad power tube. If you are blowing fuses, the problem is either the power amp circuitry or the preamp tubes.
* Leave the good power tubes in before going on to the next step. Also: the minor difference in bias wont matter for what we are doing now: the bias being WAY out is almost never the cause.
(6) Check preamp tubes (easy to do, as this does not require us to poke around on the insides).
(7) Replace burned out fuse (atleast number two by this point).
(8) Replace all preamp tubes.
(9) Turn on and repeat step 5.
* Blowing fuses at this point means atleast two types of repairs needed: retention tube sockets or someone to look inside the amp. Either way, this is a serviceman repair (things I do). Since the amp is so new, take the warentee buyout and throw it back to where you got it. Crate is real good about dealing with these issues (if you are the only owner and it is within warantee).
If you need to contact warantee support, you can tell them you have had the amp re-tubed and the problem still persists (meaning they can brush you off with 'just get it retubed and then call us if there is problems'. This is like 'take two asprins and call me in the morning: 95% of all tube amp problems can be fixed by this (retube, not asprins).
If you have to do the warantee route, KEEP YOUR NEW TUBES. The preamp tubes are fine, but the power tubes may be damaged. Wait for what Crate tells you before you use them. This is if you are cheap. I would pitch all of the tubes and consider the 70 bucks as my cheap attempt to bet I am in the 95% solution number (tubes are the cause). Otherwise, the repair will cost shipping at a minumum. Dont you love it: tube amps are expensive and require someone with deep pockets to enjoy the tone. But what can we do: tubes DO sound better and when everything is working, they perform reasonably well.
BIG problem! You should NOT have replaced the fuse as additional damage has been done. I repaired a PMP5000 and I can tell you likely what you will find: The smoke and smell came from two power resistors that are part of the soft start circuit that now are toast. You will likely find several components in the main portion of the power supply that are toast. These will include transistors, resistors, diodes, and probably the small 8 pin switching regulator chip. There is a small power supply that comes on first which enables a relay that shorts out those soft start resistors AFTER the power amplifier BALANCES and normalizes.
The unit I repaired had severe damage due to arc-over at one power amp section. Three power transistors were destroyed there and board traces and charring had to be handled in that section.
The repaired unit had to be brought up with a light bulb in series with the line power cord to prevent further damage until all bad parts were discovered and repaired. You will need to take the unit to a shop that is expperienced with the product. The repair cost MAY be pretty high.
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