I never did get a response, so thought I might try again.

Clarion DXZ948RMP.

It's in a 1994 Nissan Primera, and appears to have an overheating
problem, in that after twenty minutes of high volume use, I get sound
crackles, or "clipping", short breaks in the music.

It can of course be rectified by moving the volume down a couple of
notches until it gets cooler.

I don't get an AMP GUARD notification.

I've emailed off to Clarion, who have been helpful in suggesting a
couple of things, but now seem to refuse to answer my emails.

I bought it off eBay as new, from Germany. I live in the UK.

So Im looking to fix this myself (or screw Clarion for not honouring any
form of manufacturing warranty - useless yellow card).

Any ideas? It annoys me Im not getting as much out of the unit as I could.

Several things spring to mind...

1) Is there an issue with the power lead? Im using the regular wiring
harness, but I'd guess the fact that it work for twenty minutes and then
starts to "die" indicates my wiring is fine.

2) I am achieving the correct amount of voltage on the yellow permanent
feed, at least 13v.

3) Should I just stick some fans in there? What's the best ones to use?
I don't want to stick anything to the head unit if possible...

4) The head unit has two yellow permanent feed wires, a thin one, and a
thick one. One is 3 Amp, the other is 15 Amp. They are swappable. Should
I swap them? The manual says I only need to swap if it's a Volkswagon
(I believe the main fuse for the accessory ana audio electrics on the
car is 10 Amp if that makes a difference).

Any tips?

Thanks
Simon

Hi Simon.

Let's start with attempting to find the *root cause * of the *problem*.
Adding a fan only deals with the *symptom * of extreme heat.

I can tell you that I easily suspect you have an speaker resistance
problem-i.e., one or more of your speakers has resistance that is too
low ( 4 Ohms+/-)

Here are some solid ideas:
1. Since it's a Nissan, did you replace a Bose head unit? If so, the
factory Bose speakers will require a proper install to use with
aftermarket head unit. (Like adding resistors inline to bring up the
resistance if not using the factory amps)
2. Did you measure resistance for each speaker at the radio? This is
easy, and right away will show any problems with the "load" (speaker
impedance) the radio is seeing.
3. Are the speaker leads wired properly? I.e., you're not sharing
speaker wires, right?


Addressing your questions, secondly:

-1) Is there an issue with the power lead?-
A: That is more unlikely, but always you need to DEFINITELY find out
using a voltmeter/multimeter and make sure the unit is ground to metal
of the car body/dash metal frame.
-2) I am achieving the correct amount of voltage on the yellow
permanent
feed, at least 13v.-
A: (See #1)
-3) Should I just stick some fans in there?-
A: No, you should not have to do that with a head unit. Your head
unit's life expectancy will go WAY down if you don't find the source of
the problem. (The ICs/transistors inside will not last long handling
extreme heat and current)
-4) The head unit has two yellow permanent feed wires, a thin one, and
a
thick one.-
A: You can just connect both if you like; that's not the source of the
problem...


I can tell you that as an installer, a hot head unit is 99% of the time
related to being connected to too low a resistance speaker(s).

It should not be hard to find, but be careful not to keep using your
Clarion before fixing the problem!

If you'r not comfortable troubleshooting it, find a certified installer
or someone with technical installation knowledge.

Marty


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Hi, Simon. Yes, actually, having tweeters in there will reduce the
resistance the radio sees when it's sending the audio signal (since
normally they're wired in parallel), but not when you check using a
meter. But still you should check with a meter on all wires, as you
mentioned.

If your unit is breaking up like that, I'm pretty confident there's a
short or low resistance on some/one of the output wires--that's a
typical indication of this: heat and clipping badly.

Check the wiring and let us know...if necessary I have more ideas...but
it's always best to know what you're dealing with: test test!

Marty


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If nothing else seems to work, then I would suggest looking into the
small fans that people normally put into computer casings... They run
off of 12 volts DC and use hardly any amps, so they're actually ideal.
Sorry I can't help more, but this could be a fix for what ails you!

Mister.Lull

Hi Marty,

Thanks for the reply...

Maybe I should have given some background, it's a 1994 UK model Nissan
Primera. As such, the original radio was a Clarion (albeit 12 years
old). The original speakers were blaupunkt, but due to being unable to
cope, and the rear cones just disintegrating, all the speakers have been
upgraded to JBL's all round, which according to documentation, they are
all 4 ohm speakers. I've looked all around the car, and cannot find any
indication of Active Speaker circuitry at all either in case that was
another potential avenue for investigation.

Speaker Impedence for the head unit is quoted as 4 ohm, though the
instructions say 4 ohm to 8 ohm is acceptable.

As far as I know the speakers are wired correctly. I've gone to a lot of
trouble to source appropriate adapters so everything is wired correctly
using the standard factory fitted wiring harness. With regards to extra
speakers, there's 2 in the front, 2 in the back, plus, there are two
tiny tweeters which are in the front erm, A-Pillar by the windscreen. I
wonder if that means anything?

As far as I can tell, without dismantling the car, the tweeters are
wired into the front speaker circuit of the car. Could this be causing
the problem with load?

I havent measured the resistance of the speaker circuit from the head
unit, but that's a great tip, I'll try that ASAP and report results.



The radio itself however is correctly grounding through both the aerial
and the metal frame of the dash. So I have no issues there as far as Im
concerned.

I'll have some more digging around for wiring guides, and I'll try
disconnecting the tweeters if I can and giving that a test tomorrow.

Clarion have so far been unhelpful. I found out that by having the radio
out of the dash, the radio is better able to cope with the higher
temperatures and doesn't break up so often.

Thank you for your help and your suggestions, and hope you may have some
more advice if anything I've said rings a bell.

Cheers
Simon


MartyMcLeod wrote:
Hi Simon.

Let's start with attempting to find the *root cause * of the *problem*.
Adding a fan only deals with the *symptom * of extreme heat.

I can tell you that I easily suspect you have an speaker resistance
problem-i.e., one or more of your speakers has resistance that is too
low ( 4 Ohms+/-)

Here are some solid ideas:
1. Since it's a Nissan, did you replace a Bose head unit? If so, the
factory Bose speakers will require a proper install to use with
aftermarket head unit. (Like adding resistors inline to bring up the
resistance if not using the factory amps)
2. Did you measure resistance for each speaker at the radio? This is
easy, and right away will show any problems with the "load" (speaker
impedance) the radio is seeing.
3. Are the speaker leads wired properly? I.e., you're not sharing
speaker wires, right?


Addressing your questions, secondly:

-1) Is there an issue with the power lead?-
A: That is more unlikely, but always you need to DEFINITELY find out
using a voltmeter/multimeter and make sure the unit is ground to metal
of the car body/dash metal frame.
-2) I am achieving the correct amount of voltage on the yellow
permanent
feed, at least 13v.-
A: (See #1)
-3) Should I just stick some fans in there?-
A: No, you should not have to do that with a head unit. Your head
unit's life expectancy will go WAY down if you don't find the source of
the problem. (The ICs/transistors inside will not last long handling
extreme heat and current)
-4) The head unit has two yellow permanent feed wires, a thin one, and
a
thick one.-
A: You can just connect both if you like; that's not the source of the
problem...


I can tell you that as an installer, a hot head unit is 99% of the time
related to being connected to too low a resistance speaker(s).

It should not be hard to find, but be careful not to keep using your
Clarion before fixing the problem!

If you'r not comfortable troubleshooting it, find a certified installer
or someone with technical installation knowledge.

Marty

Just a quick suggestion: You said that the head unit is 12 years old?
It may just be time for a new one. The longest I've ever had a deck
for was 5 years, and it was my understanding that they sort of crap out
after about 7 or 8 years...

Mister.Lull

Mister.Lull wrote:
Just a quick suggestion: You said that the head unit is 12 years old?
It may just be time for a new one. The longest I've ever had a deck
for was 5 years, and it was my understanding that they sort of crap out
after about 7 or 8 years...

Mister.Lull


The original Clarion was 12 years old.... I replaced it with a new
Clarion...

Sorry for the confusion.

The original Clarion really did last that long. That's why I went for
another Clarion.

Cya
Simon

Impressive...

Hi

Right, I've checked over the car... there looks like there's an oil
leak... but to the main problem in hand... :-)

With the multimeter, the rear speaker circuits (left and right) have 4
Ohm's each.

The front left and right circuits have 4.2 ohms!

The front is made up of one tweeter and one full range (I guess) JBL 4x6
speaker.

The JBL's are rated 4 ohm.

The tweeters themselves are made by Clarion, and are also rated 4
ohm/8W. The multimeter says they're actually 4.2 ohm. Along with the
tweeter is also a Bipolar 50v 4.7 microfarad capacitor.

I've removed the tweeters, but the multimeter then reports 4.3 ohm on
the front circuits.

Im confused then.

Are the tweeters and JBL's running in parallel or serial? I guess it
must be parallel, or removing the one speaker would not produce a
reading on the multimeter. And because Im getting 4.2 on the circuit,
maybe there's another device between the radio and speaker? Either that
or the 4ohm rating isn't a true 4ohm rating. There are are also
capacitors on the JBL speaker.

I have removed the tweeters in the meantime, just to see if I get any
better results tonight for the drive home.

But if there's any further suggestions, Im all ears! Thanks for your help.

Thanks
Simon


MartyMcLeod wrote:
Hi, Simon. Yes, actually, having tweeters in there will reduce the
resistance the radio sees when it's sending the audio signal (since
normally they're wired in parallel), but not when you check using a
meter. But still you should check with a meter on all wires, as you
mentioned.

If your unit is breaking up like that, I'm pretty confident there's a
short or low resistance on some/one of the output wires--that's a
typical indication of this: heat and clipping badly.

Check the wiring and let us know...if necessary I have more ideas...but
it's always best to know what you're dealing with: test test!

Marty

"MartyMcLeod" wrote in message
news:1114564708.20d61e5d672db1ef9a56ada616ab15d7@t eranews...

Hi, Simon. Yes, actually, having tweeters in there will reduce the
resistance the radio sees when it's sending the audio signal (since
normally they're wired in parallel), but not when you check using a
meter. But still you should check with a meter on all wires, as you
mentioned.

If your unit is breaking up like that, I'm pretty confident there's a
short or low resistance on some/one of the output wires--that's a
typical indication of this: heat and clipping badly.

Check the wiring and let us know...if necessary I have more ideas...but
it's always best to know what you're dealing with: test test!

Marty

Yeah but the impedance of the mid/woofer is so high at the point where
tweeters come into play it evens itself out. So if you have 4 ohm tweeters
in paralell with 4 ohm woofers with only the tweeters crossed over the
inductance of the woofer voice coil will prevent the head from seeing a 2
ohm load. Remember we are talking impedance not resistance.

Chad

Still the same clipping and overheating problem with the tweeters removed.

So those aren't the direct problem then.

Cya
SImon