jbl 601.1 car audio amplifier

I would also like to point out, if you look at his attachment in post 32 you can make out the location. Look closely it shows a rectangle.

My amp in location C108 is a round part that looks like a CAP. It has the negative leg marked, its 16V 10uF. The board then has the + hole marked and the cap is in properly. There is clearly a mistake somewhere...

C108:



C406 and C111 are little yellow colored "things" that resemble a resistor...C406:


C111:



I have probed JBLs parts person and they are sure its whats listed. There obviously was a change made somewhere... Not documented of course.

These amps are only made to take 5V inputs. Some Head units are capable to 8V and then you have line drivers upto 13V... So im assuming someone over did it.
 
Last edited:

thatoneguy

Joined Feb 19, 2009
6,359
The tan stuff is guts from an electrolytic capacitor.

You'll want to go over the ENTIRE board and get rid of tiny chunks of "tin foil", size of this period tiny ->.

They vaporize when they die, as you can see from the pressure effect and the paper stuck to various protruding items. There was just as much aluminum inside as paper, so that's the first thing to get cleaned up, otherwise adding power can cause more things to blow that were previously unrelated.

Once the electrolytic caps are replaced with the proper value/rated, use a meter to make sure outputs NOT are shorted to ground/power/input, +12V isn't shorted to ground. input or output, and ground isn't shorted to inputs.

--ETA: I'd replace All of the electrolytic caps near the front with Sanyo "Low ESR" caps that are automotive rated (Digi-Key has that info in the ordering matrix). You'll end up saving some money by getting over 10 of the same value in a few cases.

Also, in the photo on this page that shows a hand and screwdriver, the "bottom" capacitor in the row of three next to the toroid looks bulged along the stress lines. The toroidal transformer and capacitors in that area are all part of the power supply, so if any look to be bulged like that, replace the bank of of them. High ESR caps/dried out caps generally happen at the same time, it's rarely just one on the board. Without an ESR meter, or a LCRZ meter, it's difficult to tell which ones need replacement unless there are visible signs. If this is a one time change out, the cost of new caps would be much less than a tester.
 
Last edited:

thatoneguy

Joined Feb 19, 2009
6,359
Are C101, C104 and C108 all the same value/voltage rating?

The vaporized one appears to have the same footprint and height as those, from the images. If the are all the same value, or if the blown capacitor connects the power and ground planes, I would guess the blown up one is the same as well.

The only problem with that SWAG is that 2 capacitors of the same physical dimensions can be wildly different. Such as 47uF/10V, or 4.7uF 50V are very close. If what the capacitor is connected between is known, it will help decide. Other option is to use google image search to see if somebody else has posted an image of their amplifier with a different cap blown, and you can read the value of the one you are missing from it.
 
C101 & C104 are 22uF 16V

C108 is 10uF 16V


SWAG?

Sorry for my ignorance. I took Electronics 101 in College and soem AC/DC classes. Mostly towards Industrial Electrics like wiring machines, etc. Been about 6 years... :)

Update!

The information listed by the OP reflects the JBL 601.1 Mine is the JBL 601.1 II (version2). It may be possible they used the old boards but put the NEW parts on it- which is what I think happened.

Ref material:
http://ampguts.realmofexcursion.com/JBL_GTO601.1/
 
Last edited:

thatoneguy

Joined Feb 19, 2009
6,359
SWAG is a very technical term for "informed hunch" ;)

Scientific
Wild
Assed
Guess

On the amp, maybe if you contact JBL to get the value of the cap, and mention it is the 2nd revision board, you'll get the correct value? Can you take a photo closuep of both the top and bottom of the board where those caps are? If it is a filter/input cap, the value is more sensitive than if it is a bypass cap.

It is common for circuit boards to be common to more than one amp, and even between some manufacturers. The cost of layout/design/build is quite high, so a large number are made to get the unit cost down. Then the boards are modified if needed to be used in a similar application. Sometimes they are sold to a different manufacturer who uses them in a similar application. Components themselves are relatively cheap until reaching the electroylitic caps, tranformers, output transistors, and the chassis/heat sink.
 
Amazingly someone from the car audio message boards has these amps.

Heres the kicker, the area was affected by the revisions...

Version 1:


Notice what C107 and C108 are. They are yellow...

Version 2:



So hopefully this can provide some closure to the OP also. Ive been working hours tonight to identify this issue... Hopefully all the info in this thread (most information Ive found) will help others.
 

SgtWookie

Joined Jul 17, 2007
22,220
SWAG = Scientific Wild-Arsed Guess. :D

From your Post 41 in this thread:
My amp in location C108 is a round part that looks like a CAP. It has the negative leg marked, its 16V 10uF. The board then has the + hole marked and the cap is in properly. There is clearly a mistake somewhere...
Actually, that's OK - as long as the polarity is correct.
When your new radial-lead caps arrive, you may notice that the negative lead is shorter than the positive lead; this is normal. If the caps were being manually inserted at the factory, it would be more helpful to the assembler to have the hole for the longer + lead marked, which would be inserted first.

As long as you're replacing capacitors, you might as well replace ALL of the electrolytic caps. They aren't that expensive, unless they blow up on you - then they can take out surrounding components, as well as traces on the PCB. Electrolytic caps tend to have high leakage currents after they've been sitting around for a few years. High leakage currents = heat buildup = boiling electrolyte = blown up caps = dead circuit.
 

thatoneguy

Joined Feb 19, 2009
6,359
As long as you're replacing capacitors, you might as well replace ALL of the electrolytic caps. They aren't that expensive, unless they blow up on you - then they can take out surrounding components, as well as traces on the PCB. Electrolytic caps tend to have high leakage currents after they've been sitting around for a few years. High leakage currents = heat buildup = boiling electrolyte = blown up caps = dead circuit.
This.

There are still things dying daily from the 4 years of bad caps put out. Computer motherboards were the first effected, but now everything from car audio to fax machines to microwave ovens are suddenly quitting due to bad caps.

Good Electrolytics start with only a lifetime under 10,000 hours, but when their formula is messed up (2002-2005), it drops quickly, depending on load. They also fail spectacularly, often wiping out several other parts due to shorts.

Replacing all of them yourself would cost less than an estimate at a stereo shop for repair, provided you have the tools: 20W soldering iron w/fine tiip, desoldering wick or solder bulb, solder, tweezers.
 
Thanks for the replies guys!

Im venturing into Amplifier repair. I have a Weller WLC-100 w/.06" tip. I bought some Chem-Wic desoldering braid w/good recommendations. Works good!!! Before that I had some other stuff and had to apply flux to it for it to work :(

I bought 10 of each caps for that area- whole $0.77 for 10- lol.

I also reviewed the caps on the power supply side. Thatoneguy got me a little nervous :) The on cap on the end appears to be slightly different than the others (end wise). So Im replacing all of them also. However they are GLUED to the board :(

My total order @ digi-key was like $13....lol Needed some sil-pads and 2 caps for an MTX amp Im working on.
 

Thread Starter

craig155

Joined Jul 21, 2008
33
Looking more closely at the board you can see scorch marks, i dont know if they are of the blown capacitors or something more.
Any ideas guys?
 

Attachments

thatoneguy

Joined Feb 19, 2009
6,359
Board looks overheated from Q208 and Q210 getting too hot, or a component on the other side of the board from them. If the resistors were the reason for the darkening, they'd be unreadable.

To test the relay, You should get between 50 and 150 Ohms across the coil, marked by the curly line.

Then there are three other connections: Common, Closed, Open

When there is no power to the relay, there should be very low resistance between the common and one pin. When power (12V) is on the coil, it should "click", and then there should be low resistance between common and the other pin. In both cases, the pin that isn't connected should have very high resistance, and usually not have continuity to the coil at all.

I'd guess the bottom center pin as Common, but that's just a guess.

As far as the capacitor, the tan ceramic in the early photos appears to be WAY to small of a value, ceramics are usually picofarad/nanofarad range, whereas electrolytics are in the microfarad range.
 

Thread Starter

craig155

Joined Jul 21, 2008
33
According to the schematic i need ceramic tubular 102pf 50v capacitors, like C111 does this sound right?
Strange that the board came with electrolytic capacitors 10uf 16v??????
 

Attachments

Top