You can use it to measure voltage but you cannot use it to directly measure the current draw of the amplifier.
You need to 'zero' the meter movement. Lay the meter flat and gently turn the slotted adjustment below the meter movement until the needle is aligned with the leftmost line of zeros.
You need to 'zero' the meter movement. Lay the meter flat and gently turn the slotted adjustment below the meter movement until the needle is aligned with the leftmost line of zeros.
okay so ive decided to buy a new multimeter to help with this fix. i have seen this one http://www.maplin.co.uk/module.aspx?moduleno=46390
would that suffice to what ill need to check? it says it can check up to 20amps current draw... would that be enough? thanks
would that suffice to what ill need to check? it says it can check up to 20amps current draw... would that be enough? thanks
Measuring the current draw isn't absolutely necessary and could be be done with your meter (and a current shunt resistor) so don't buy a meter just for that.
I have no experience with that meter but having a digital meter would make things a bit easier. Having the diode-check function may be helpful.
I have no experience with that meter but having a digital meter would make things a bit easier. Having the diode-check function may be helpful.
sorry for the delay perry... im just waiting on my local electronics store to get some new solder tips in stock as mine has crumbled a lil so dont really want to use it. will update you once the new fets are installed and ive done the checks you told me to do. thanks 🙂
okay so ive installed the new FETs. checked from the gate leg and ground terminal and yes it does show 110ohms. ive connected the board back into the amp, i have connected the two channel wires and the 10 connector cable but i havent connected the 6 connecter cable. what should i do next? i feel scared to power it up lol. Im still using the analogue meter i have as i havent bought the new digital one. thanks 🙂
For the positive rail, set your meter to the lowest range that can read 50v DC. Place the black meter probe on a non-bridging speaker terminal. Place the red probe on pin1 of the 6 pin connector (don't let the probe slip!). Adjust VR601 so that you read 49v.
For the negative rail, place the RED meter probe on a non-bridging speaker terminal. Place the BLACK probe on pin 6 of the 6 pin connector (again, do NOT slip). Adjust VR602 so that you read 49v.
If you place your black probe on pin 6 of the 6 pin connector and the red probe on pin 1 of the 6 pin connector, you should read 98v DC.
Don't forget to zero your meter movement before doing this.
For the negative rail, place the RED meter probe on a non-bridging speaker terminal. Place the BLACK probe on pin 6 of the 6 pin connector (again, do NOT slip). Adjust VR602 so that you read 49v.
If you place your black probe on pin 6 of the 6 pin connector and the red probe on pin 1 of the 6 pin connector, you should read 98v DC.
Don't forget to zero your meter movement before doing this.
just to make sure.... pin1 on the 6pin connector is on the top if the power and chassis ground terminals are on my right? and the positive rail is the top one if the terminals are still on my right? and im connecting the probes onto the power board? sorry i just want to make sure i do it right as i dont want it blowing again. thanks
Yes, pin 1 at the top.
The positive rail is connected to pin 1 of the 6 pin connector.
One probe will go on the 6 pin connector. The other will go on a non-bridging speaker terminal. If I'm not mistaken, you have all of the wires connected to the audio board except the 6 pin connector, correct?
The positive rail is connected to pin 1 of the 6 pin connector.
One probe will go on the 6 pin connector. The other will go on a non-bridging speaker terminal. If I'm not mistaken, you have all of the wires connected to the audio board except the 6 pin connector, correct?
yes everything is connected except the 6 pin connecter... ive unplugged it from the power board... so it is just the socket on the power board and the cable is only attached to the amp board
ive just plugged it in. had the probes like you said but my meter was not picking anything up on 50v dc mode but on 10v mode the meter was going off the scale... it may be the meter so i will get another one just to make sure. The protection and power light were still flashing red but the music light was green. i know you said make sure the probe does not slip but because the power supply is coming from the car i was doing it inside the car and because the amp was not stable on the seat the probe slipped on pin1 and touched the the channel terminal near it 🙁. there was lil spark/blow but the amp was still on and worked the same. but now ive just checked over the FETs i changed between leg 2 and 3 and they all are sending the meter off the scale :S past 0. 🙁 does this mean its completely gone? im sorry to have wasted your time. i guess some things are left to professionals.
huh... hold up.... ive just checked them again and now they are showing resistance...that was weird... will have to get hold of a new meter or is there something im doin wrong? because i also checked a car battery... it went off the scaled on 10v dc mode but showed nothing on 50v dc mode.
It appears that the 50v range isn't working properly. Try to borrow a digital meter.
When it sent the meter off of the scale when measuring the resistance, it was likely due to voltage across the terminals you were probing.
When it sent the meter off of the scale when measuring the resistance, it was likely due to voltage across the terminals you were probing.
hi perry. i bought that multimeter i showed you and ive set vr601 and vr602 to 49v exactly like you said. The protection light and power light still flash red and music light is green. should i try with the 6 pin connecter back in?
You were using a 15 amp fuse in the B+ line before. Reduce that to a 10 amp and see if the power supply will power up without blowing the fuse (6 pin connector disconnected).
If it doesn't blow the fuse, let it run like that for ~10 minutes. If it remains cool, turn it off, reconnect the 6 pin connector, set the bias pots fully counter-clockwise and power it up. Does it blow the fuse?
If it doesn't blow the fuse, let it run like that for ~10 minutes. If it remains cool, turn it off, reconnect the 6 pin connector, set the bias pots fully counter-clockwise and power it up. Does it blow the fuse?
okay cool will try that tomorrow. just to double check again, the bias pots are the ones on the amp board? vr401 and vr402? i know youve told me before but just want to make sure.. and turn them clock wise fully? thanks
jus done that. with the 10amp fuse, 6 pin connector conected and the bias pots fully counter clockwise the fuse did not blow. i let it run for 10minutes. the protection light and music light now stay green however the power light still flashes red.
Measure the DC voltage across the speaker terminals for each channel (no audio). If the voltage is well under 1v, connect speakers and a signal source to it to see if it will produce audio.
Be sure all transistors are tightly clamped to the sink.
If it produces audio, play it at low volume for 10-15 minutes to see if it gets hot or has any other problems.
Be sure all transistors are tightly clamped to the sink.
If it produces audio, play it at low volume for 10-15 minutes to see if it gets hot or has any other problems.
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