• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

GK pink ring of doom

Brainmisspelled

Brainmisspelled

Jan 23, 2022
17
129
New Jersey
#1
So I started to get the pink ring of doom on my GK mb115 (where the ring around the power button goes from red to pink rather than red to blue upon power up) after lots of reading I found out this means the power amp is fried so I ordered a new 50ASX2BTL power amp. It didn’t seem like replacing it would be very difficult as it’s just 4 screws and 6 plugs to disconnect and reconnect.

I’ve now installed the new power amp and there is no light at all around the power switch! Figuring I probably put it in wrong so I tried installing the old one to see if I could atleast get the pink ring of doom back…i figured if I put the old one back in and get it back to what was happening before than I must be installing it right….sure enough when I put the old power amp board back in and power it up it works like it used to (red to pink) so it seems like I’m assembling it right.

i put the new one back in AGAIN and again nothing. No lights no sounds no action.

does anybody have any ideas on what I should do now? Did I miss a step somewhere or something? Possibly the wrong part? (I don’t think so because I asked Gk what to get) maybe I just got a bad replacement power amp? I donno I’m lost at the moment so any help other than call Gk would be appreciated. Thanks
 
#2
A couple of possibilities, the first being that there is another fault in the amp and new the replacement part is damaged.

The other possibility is that you bought a counterfeit power amp module. If it came from China or Hong Kong, it’s almost certainly counterfeit (even if it looks legit).

This is why troubleshooting is important, identifying the actual fault, and verifying that there is no additional damage.
 
  • Like
Reactions: Afc70, SirMjac28, mb94952 and 9 others
#3
I think I actually found the problem…I ordered it from parts-express.com…GK recommended them so I don’t think it’s a counterfeit.

…it’s certainly not well produced though because it’s missing 3 resistors…I’m thinking I was just sent a bad part. What do you think?

side by side
B3E76157-DCEA-48C6-AE9E-E2C7712F6FAA.jpeg


old one
D8147D1E-F509-4600-999B-CF9D16C11254.jpeg

New one
5F5366D1-2FED-4D4A-8EB6-C6DB03325655.jpeg
 
  • Like
Reactions: mb94952
#5
I don't think those parts have anything to do with your problem. There are different evolutionary versions of this module.

Either the module is defective or there is more wrong with your amp that's causing the issue with this module and the new module is now damaged.
 
  • Like
Reactions: SirMjac28, Mechanical, Al Kraft and 5 others
#6
I think missing 3 resistors constitutes defective…and would explain the results I’m seeing.

The new one when installed shows now sign of power at all…like the circuit is broken somewhere…like those three places there would usually just be a little electrical resistance.

the pre amp and speaker work so the problem is definitely in the power amp board…I’m putting the boards in correctly because I can put the old one in and it atleast gets back to where it was, so the problem is in the new board…which is missing components. I’ve poured over them both…everything seems to be the same except it’s missing 3 resistors…so I don’t think it’s a different build of the power amp board because it looks identical. I think I just got one that had an error in manufacturing.

why don’t you think it’s this?
 
#7
No, it doesn't explain what you are seeing, you just don't know what you are looking at and are unwilling to listen to somebody who has 20 years or working directly with IcePower and their products. The most recent revision does not have these resistors installed, I looked at my docs and they are not supposed to be there. They are part of a high voltage bleeder or snubber that's not needed. I have one here without those resistors and it works perfectly fine.

You are new here, you asked for help, you got more than qualified help, and now you are arguing with me? C'mon, maybe you don't know as much as you think you do, that's fine, but don't argue with someone who understand more than you do about this.

Now, the most common causes for a new module not operating is either a missing BTL programming jumper (some versions have this and some don't, because some boards were configurable for dual single ended or BTL) and the other common cause is a failure of the installer to understand that the power supply needs to be jumper configured for 115/230V. Fortunately for you, you didn't realize this and your module is factory configured for 230V and must be changed to 115V in order to work properly in the US. This, of course, has nothing to do with the missing resistors.

Change the jumper (disconnect from the power source first).

Another common cause of damage to these modules is rough handling which physically damages components on the bottom of the PCB. I see a few modules a year returned by techs claiming defective when in fact they damaged the modules themselves.
 
  • Like
Reactions: AJClone, Jakedog, Rabidhamster and 48 others

Latest posts

Top Bottom
Back