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Sudden amp issues...

BPortas92

BPortas92

Guest
Jan 23, 2017
23
20
York, UK
Disclosures
Gear4Music
#1
Hi all,

First post for a while, but I made plans to sell my backup amp this coming weekend and upon moving my amp downstairs for the prospective buyer to examine, a coupld of deal-breaking problems have arisen. For reference, the amp is an Ashdown MAG250 4 x 10 combo. I've had it for about 2 years, and has never let me down until today. Quick answers would be really appreciated, so I can inform the buyer (who is driving 50+ miles to collect) if it's now unsuitable for him.

The amp now takes an age to produce output - I press the power button and the fan comes on instantly, but the actual signal itself comes on about 3 to 5 mins after the power switch is pressed. This never happened before, with a maximum wait of 20 seconds before signal came through.

The main issue is that now, the power cable socket seems loose somehow, which seems to be causing the signal to drop out...I've taken the amp component out and though my experience with amps is limited, nothing appears out of order. What's weird is that the power stays on (VU meter registers signal from the bass and fan continues working), but output cuts in and out when the power cable is moved. I initially thought this could be the jack connection to the speakers (built into the combo), but this has been ruled out.

Any insight would be useful - it's an old amp, but has not had any problems in the whole time I've owned it. I doubt pictures will be useful, but can provide if needed.

Thanks everyone!
 
#2
A qualified service tech would be capable of troubleshooting through diagnostic steps that accurately identify the cause of the problem. Once the cause is identified, the solution should be straight forward.
 
#3
If i remember there is a relay delay start for the main amp. Contacts are old on the relay or check the jfet circuit that controls the relay. Few electrolytic caps in the timing circuit and check voltages around the diodes in relay circuit. Any large ceramic dropping resistor for low voltage. Check for tolerance and they make a ton of heat and can cause bad solder connections on the the board near the resistor
 
#7
Old Garage-Bander said:
The capacitors must be good because they never fail. Replace everything else.:roflmao:

Seriously. You need to find a tech to "bench" this for you.
Good Luck. Hope it's something simple.
Click to expand...

It COULD be a defective cap, but without proper troubleshooting it could just as easily be something else. ;)
 

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