m44 sub output problem help?

[gabriul]

So, I have had my PG m44 for about 4 years now, ran it for about 1 year and then put it up in storage untill a few days ago. I bench tested the unit with a couple MB quarts and a Xtant 12 sub. Everything seemed great. So, i went and installed in my truck. Still, everything was great.

Sub was to big for the truck, blah blah blah, installed a JL 10"

Now there is zero sound coming from the sub? If I am in the "internal" cross over mode, and using the second channel as just a rear speaker amp, sound comes out fine. Its just in the external crossover mode that no sound is coming out.


There are two areas on the PC board that seemed to have gotten pretty warm. Both on medium resistors?

Any help or direction would be most appreciated!!

Thanks

Gabe



Pics to come soon.

[fuzzysnuggleduck]

Describe how the sub is wired up to the M44 and how you've got the RCAs connected. Do you have both front and rear RCAs connected or are you just using the front input?

In external xover mode, signal for the rear channels comes from the rear RCA inputs. If you're only using one set of RCAs into the amp (front input) and trying to drive both the front and rear channels, you need to set the amp to "internal".

[gabriul]

ahh, sorry for not stating that.

I am using both sets of RCA's front for the front MB quarts and rears for my sub.

I have hooked up the sub from left+ to right- according to the back of the amp for mono sub output.

Hope that explains it better!

Thanks again

[gabriul]

So, nothing looks terrible. But, at the same time, the two resistors did get hot. Does that help?[/img]

[kg1961]

did you try to change the 2 set of rca to see if its the rcas?

[oldschoolfan]

I have a Route 66 and on the M44 side those exact two resistors you have pictured both smoked. It was repaired at PG and they piggy backed two resistors for each location, so now there are four there. I don't have it apart or I would tell you what the ratings are on the resistors they way they set it up.

This looks like it may be a common problem. Any M44 owners out there that can add to this?

[Misfire]

I know the M44 I have a Bogart's getting recapped has the same issue. They are working, but the board looks exactly like this one on the back. I would like to get some pictures of the doubled up resisters.

[oldschoolfan]

I know the M44 I have a Bogart's getting recapped has the same issue. They are working, but the board looks exactly like this one on the back. I would like to get some pictures of the doubled up resisters.

Good call. Thanks for asking for the pictures. I forgot that I took some. It appears the resistors are 200ohm each. Now I don't know how that works with them being tied together like that, resistance properties and all. I am going to post this picture huge so you can zoom in and see in detail, well as best as possible anyway. I have a terrible time getting good close up circuit board pictures.

[ttocs]

correct me if I am wrong but those bands look to be brown brown black. its been a while, but isn't that an 11 ohm resistor?

[gabriul]

Gold brown black red on the above picture.

On my 44 it seems to be gold brown black gold.

putting two resistors like that just doubles whatever they are. IE: two 4 ohm in paralell would be 8 ohm.

so, if those are 200 each, would put them at 400 ohm?

I tested my resistors and they showed 110? so... hmmm

Resistor chart I found wasn't worth looking at.

Anyway, it looks like the update is 400 ohm. while mine are 100 at 5%?

It would be neet if there was a before picture of someone elses also, but i know thats allot to ask for. HAHA

[Misfire]

Thanks for the pics!!

[andy600rr]

Standard resistor appears to be brown/brown/black 5% tolerance (11ohms) as ttocs said.

Doubled up resistors are red/black/brown 5% tolerance (21ohms but 2 in paralell will halve the value so 11.5ohms) but double the wattage for heat dissapation due to the 2 resistors.

I posed the question to Eric some time ago about replacing these very resistors in my M44 with ceramic items to dissapate more heat since mine are the same. Seems to be a common issue.

[gabriul]

I'm terribly confused.
When i do the conversion charts, red black brown gold comes up with 200ohm? What am I doing wrong?
red brown black gold, comes up with 21ohm...???


I know that I'm dislexic, so that would explain the X2, as to /2 when doubling up.

So, is that a 20k resistor or 20 ohm resistor?

[gabriul]

Headed to store to get resistors.

Prolly just replace with the doubled 21 ohm!

Not to much of a loss I suppose


edit:
Swapped for the double 21. Bad news bears. Smoked the new resistors. Not quite sure whats going on, but I think I'll swap back to a new set of 11 ohm.

Guess I only have time wasted.


any other thoughts of whats going on??

[oldschoolfan]

I'm terribly confused.
When i do the conversion charts, red black brown gold comes up with 200ohm? What am I doing wrong?
red brown black gold, comes up with 21ohm...???


I know that I'm dislexic, so that would explain the X2, as to /2 when doubling up.

So, is that a 20k resistor or 20 ohm resistor?

I too am confused. I read 200 ohm on the chart also...

[joerg]

putting two resistors like that just doubles whatever they are. IE: two 4 ohm in paralell would be 8 ohm.

so, if those are 200 each, would put them at 400 ohm?

I can´t help with fixing your amp but u got the math terribly wrong here!

Two resistors of 4 Ohms in paralell will give u 2 Ohms! So if those 2 are 200Ohms each it should show u 100 Ohms in total!

Two resistors of 4 Ohms in serial will give u 8 Ohms in total!!!

[joerg]

Some more info!

You need to decode your resistors with a 4 band chart! You always start to read from the side with the bands close to the next one! Gold is a colour u won´t find in the first band at any time!!!

Your resistors appear to me like they are: red brown black gold! (Better pic will help)
This brings me to the conclusion that we have a resistor with 21 Ohms right here! The gold band is the tolerance of +/-5%

Down below is the chart for it.

[bogart]

good job Joerg...I was just trying to load a chart up....the resistors are an issue...and there is a diode in the circuit that is bad on leeds as well...if I am not mistaken they are part of a gate coming right off the rails into the circuit and get hot as hell...they are used if I am not mistaken to pull the voltage down and stabilize the load before it goes thru the bjt's in the audio side...

find the value and the you know the tolerance and find the ones with the greatest mass....as long as it is an axial lead and it is the same length...the oem resistors don't have enough mass to dissipate the heat and we are talking m amps that run hot anyway....

the length of the resistor is generally an indicative of the components wattage value....so find the same length...but look into a newer thicker style...you can also install them up off the board too...as far away from the caps as you can get em and insure that they are stable...little silicone under them and they should be ok....

I will look at the one here tonight and get the diodes number on the board and any other significant components in the circuit that you should check...when you check the resistors in the circuit be sure to lift one leg so the you arn't reading the sum value of the circuit itself....

a diodes tolerance can be askew also and generally when you see real resistor issues there is a reason for it...a component in the circuit is out of tolerance and the resistors are seeing to much current...more then they were designed to withstand and rectifiers and single stage diodes can often be the source of the problem....

[ttocs]

you have two different pics there. The one I commented on, brown brown black is an 11 ohm resistor(brown =1, black =0)

The red black brown would be a 200 ohm resistor.

[oldschoolfan]

you have two different pics there. The one I commented on, brown brown black is an 11 ohm resistor(brown =1, black =0)

The red black brown would be a 200 ohm resistor.

Thank you for your cyphering. I was starting to think I could not count.

[ttocs]

the pic he posted is good as a visual, but the easiest way to remember is that Bad Boys Rape Our Young Girls But Violet Gives Willingly. My electronics teacher only had to tell me that once and that was my freshman year when I really didn't care.

Black - 0 Bad
Brown - 1 Boys
Red - 2 Rape
Orange - 3 Our
Yellow - 4 Young
Green - 5 Girls
Blue - 6 But
Violet - 7 Violet
Grey - 8 Gives
White - 9 Willingly

[oldskoolmseriesfan]

[quote="ttocs"]the pic he posted is good as a visual, but the easiest way to remember is that Bad Boys Rape Our Young Girls But Violet Gives Willingly. My electronics teacher only had to tell me that once and that was my freshman year when I really didn't care.

Black - 0 Bad
Brown - 1 Boys
Red - 2 Rape
Orange - 3 Our
Yellow - 4 Young
Green - 5 Girls
Blue - 6 But
Violet - 7 Violet
Grey - 8 Gives
White - 9 Willingly[/quote

Nice one ttocs but this is what I came up with in trade school
big
breasted
raunchy
orgy
yet
gives
bitches
vaginas
great
workings

[gabriul]

So, what I'm reading is that the PG repair persons are replacing 11 ohm resistors with doubled 200's. So, bringing them to a 100 ohm resistor?

This doesn't exactly make sence to me.


My old resistor read about 94 ohms?


Any luck on the diode location and number?

[bogart]

I got swamped this weekend...will be back in the shop room this evening and I will get you some more info and some pic's....sorry for the delay....

[dwnrodeo]

So, what I'm reading is that the PG repair persons are replacing 11 ohm resistors with doubled 200's. So, bringing them to a 100 ohm resistor?

This doesn't exactly make sence to me.


My old resistor read about 94 ohms?


Any luck on the diode location and number?

Mine was around 91 ohms too.

http://phoenixphorum.com/m44-cap-replac ... eplacement