Response Amp Fitted: Works intermittently

[djroberts]

Hi there,

Recently i purchased a new response 5 channel amp and fitted it to the vehicle. It is connected to a Pioneer Premier head unit (cost about $700 2yr ago) and runs through a 2 Farred capacitor. When it works the stereo sounds tops but it only works, as i said, intermittently.

Syptoms include:

-> 13v between + and - at amplifier (when it doesn't work)
-> 11.5v when system is on @ amp 'on' switch (when it doesn't work)
-> Red off light illuminated on amp when system on (when it doesnt work)

-> Green light illuminated on amp when system on (when it does work)
-> 12.9v between + and - at amplifier (when it does work)
-> 12.05v when system is on @ amp 'on' switch (when it does work)

The vehicle was in the same condition electrically (no fan etc.) when tested.

My suspicion is it's the signal from the H/U to the Amp to switch it on. Either an issue with the H/U or amp.

Recently blew a sub-woofer amp (hence the new amp) i don't know if this is coincidence or not.

Connections are good - Soldered joints wherever possible.

Doesn't make any difference if car is running or not.

System sound is excellent when it works.

Happy to put photo's up if requested.

Any thoughts?

Cheers, D.

[tehekho]

Short across high output on amp.
Or too low impedance

EDIT:

Else I'd be saying check your earths - but you've assured us that connections are good.

Sounds like its hitting protect mode though...

[-Scott-]

Syptoms include:

-> 13v between + and - at amplifier (when it doesn't work)
-> 11.5v when system is on @ amp 'on' switch (when it doesn't work)
-> Red off light illuminated on amp when system on (when it doesnt work)

-> Green light illuminated on amp when system on (when it does work)
-> 12.9v between + and - at amplifier (when it does work)
-> 12.05v when system is on @ amp 'on' switch (when it does work)

What I see:

Presuming there's no other significant differences in the state of your electric system, there's a minor difference in supply voltage at the amp between when it's working and when it's not. That difference could be explained by voltage drop in the supply cable, and probably not significant.

There's over half a volt difference at the "on" terminal when it's not working vs when it is. I can't think of any reason why there should be that much difference, and it's probably why the amp doesn't turn on - if the "on" signal isn't close enough to the supply voltage, that could be the problem.

The next time the amp doesn't work, do two things:
1. Measure the voltage of the "on" signal at the head unit. If should be essentially the same as the voltage at the amp.
2. Jump the "on" signal direct to the supply terminal and see if that solves the problem. If it does, I would say the problem is in the line connecting the "on" signal from head unit to amp.

[djroberts]

Syptoms include:

-> 13v between + and - at amplifier (when it doesn't work)
-> 11.5v when system is on @ amp 'on' switch (when it doesn't work)
-> Red off light illuminated on amp when system on (when it doesnt work)

-> Green light illuminated on amp when system on (when it does work)
-> 12.9v between + and - at amplifier (when it does work)
-> 12.05v when system is on @ amp 'on' switch (when it does work)

What I see:

Presuming there's no other significant differences in the state of your electric system, there's a minor difference in supply voltage at the amp between when it's working and when it's not. That difference could be explained by voltage drop in the supply cable, and probably not significant.

There's over half a volt difference at the "on" terminal when it's not working vs when it is. I can't think of any reason why there should be that much difference, and it's probably why the amp doesn't turn on - if the "on" signal isn't close enough to the supply voltage, that could be the problem.

The next time the amp doesn't work, do two things:
1. Measure the voltage of the "on" signal at the head unit. If should be essentially the same as the voltage at the amp.
2. Jump the "on" signal direct to the supply terminal and see if that solves the problem. If it does, I would say the problem is in the line connecting the "on" signal from head unit to amp.

Hi Scott,

Thanks for the reply, I didn't measure the voltage at the H/U because I had already re-assembled the dash on the 80 however, i did try jumping the signal with a test lead from the supply terminal and found it didn't work. I can only assume from that, even if the supply from the H/U is wrong, that the problem lies withing the amplifier itself?

Upon further investigation, i found the red light i had previously thought was the off light is in fact the system protection light. Indicative of a wiring issue. I maintain that the wiring is correct, I've checked three times? Why would it still work beautifully sometimes??

Is there anything else i can do to pin point the issue?

Cheers, D.

[tehekho]

Protect Mode = Too Low Impedance most of the time, possibly too low supply voltage.

Voltage drop down the remote line shouldn't affect the amp unless you're dropping half the voltage or more.

How many woofer doofers do you have? And Speakers? Are any of the channels wired to speakers running in series or parallel??

[tehekho]

Could also be heat, although I assumed you would have told us if the thing was getting hot enough to singe your eyebrows off...

[djroberts]

Ok, thought some pics might help...



















I did a bit of research on Capacitors and found that they need to be slowly pre-charged through a resistor under about 100 ohm. Is it possible, through naivety, that i have damaged the capacitor which may be cause an occasional short (it seems to be automatically controlled ie. no external switch for on/off)? It's a Jaycar 2 farad type: http://www.jaycar.com.au/productView.as ... rm=KEYWORD" onclick="window.open(this.href);return false;

[dogbreath_48]

Havent pinched a speaker wire in a door like i did?

I had a similar problem with an early jaycar amp - at the time i figured it was an over-sensitive over-temp sensor. Never worked it out, just got a replacment under warranty, no dramas. How long does it run for, and does it restart after a certain amount of time or do you have to 'reset' it? Does volume affect how long it runs for?

[phippsy]

Just wondering how good the earth is on that seat rail bolt, my only thoughts so far...

[djroberts]

Havent pinched a speaker wire in a door like i did?

I had a similar problem with an early jaycar amp - at the time i figured it was an over-sensitive over-temp sensor. Never worked it out, just got a replacment under warranty, no dramas. How long does it run for, and does it restart after a certain amount of time or do you have to 'reset' it? Does volume affect how long it runs for?

If it starts working it will keep working until you do something like change a CD (which inadvertently turns the amp off). It seems as though it likes a cold start but hates a hot start?

I ran wires through conduit and checked continuity in the lines, so i don't think its a crushed line.

Anybody have any thoughts on the capacitor issue i previously mentioned?

Starting to think it a crook amp - might be warranty job.

Cheers - D.

[-Scott-]

If you suspect it's the capacitor, disconnect it and see if the problem goes away. It's only really needed for loud bass.

[Dooley]

Start ruling things out ?

Get the amp to bare essentials, just wire up the power with no cap and make sure that's good. Have the remote turn on just triggering off the power for now to rule that out.

If all is good then hook up your source, either use your head unit or maybe something like an ipod turned down just for testing.

Then try say some test speakers on the amp to rule out the sub.

Just do stuff like that and swap things around until hopefully something works or doesn't work and by process of elimination you should narrow down the problem.

You could check all your wiring with a meter as well.

[-Scott-]

Years ago, when I had an amplified sub in the back of a company wagon, I had intermittent cut-out problems, but I haven't been able to remember exactly what caused it. In the end, it was simple - from memory, a loose connection on the wiring to the speaker? Whatever it was, I got the shits one day on a country run, had a quick look on the side of the road and fixed it in seconds.