Hey all, got another fun project. I bought a B&K AV30.2 Amp "Brick" and was surprised to see an ICEPower 50ASX2 module in it...cool, as I have not yet heard one of these ASX units.
Anyway, the ICEPower 50ASX2 module is run in SE mode - 2 channel. It plays for a few seconds then cuts out. I have separated the preamp/buffer and ran a signal straight to the amp to determine if the fault lie with the preamp section or amp - it is with the amp.
I checked pin 1/2/3 - Enable/overcurrent/thermal pinouts. When amp is properly playing, they all show 4.89v (good). When it stops playing, the Enable pinout internally goes dead (.2v), while the other two pins are still at 5v (good).
Now according to manual, the Thermal and Overcurrent pins are output only - while the enable is both input and output - meaning an external source can pull down the 5V to 0V to shut down the amp on enable pin, AND/OR the amp can be shut down internally (sending the pin from 5v to 0v) by Thermal or Undervoltage issues. Now since the Thermal pinout shows fine at 5v (why the redundancy here?), it leaves the Undervoltage as being the culprit for the amp is going into protection...I checked and it is jumpered on 115v...
I have seen a few of these B&K AV30.2 amps that have the ICEPower 50ASX2 modules doing the same thing - play and then go silent...don't know if they modified the 50ASX2 or just an issue with the ICEpower unit itself...
Anyway, anyone have any ideas?
Anyway, the ICEPower 50ASX2 module is run in SE mode - 2 channel. It plays for a few seconds then cuts out. I have separated the preamp/buffer and ran a signal straight to the amp to determine if the fault lie with the preamp section or amp - it is with the amp.
I checked pin 1/2/3 - Enable/overcurrent/thermal pinouts. When amp is properly playing, they all show 4.89v (good). When it stops playing, the Enable pinout internally goes dead (.2v), while the other two pins are still at 5v (good).
Now according to manual, the Thermal and Overcurrent pins are output only - while the enable is both input and output - meaning an external source can pull down the 5V to 0V to shut down the amp on enable pin, AND/OR the amp can be shut down internally (sending the pin from 5v to 0v) by Thermal or Undervoltage issues. Now since the Thermal pinout shows fine at 5v (why the redundancy here?), it leaves the Undervoltage as being the culprit for the amp is going into protection...I checked and it is jumpered on 115v...
I have seen a few of these B&K AV30.2 amps that have the ICEPower 50ASX2 modules doing the same thing - play and then go silent...don't know if they modified the 50ASX2 or just an issue with the ICEpower unit itself...
Anyway, anyone have any ideas?
OK, now thoroughly confused (but happy). I hooked up the module with signal direct to the module. This time I set up the power mains to amp module from my variac and set it up to 130vac (to make up the undervoltage)...probably not a very smart thing but hey...didn't work. But for sh*ts and grins, I lowered the voltage to 104vac on varaiac and she works perfectly now. So it was an overvoltage issue...Stays on and have been listening for past 15 minutes...what the hells gives? My mains is too high at 122vac?
OK, more good news...Now I think I got it - the Variac did something to the earth ground...I replaced the variac with a Cheater Plug and now works perfectly from my mains. Leave the mains earth ground plug off and allow the amp to totally float the mains.
I knew these ICEPower ASX Modules were a little goofy about the grounding but this is crazy...
Well, thanks for the help everyone!!
I knew these ICEPower ASX Modules were a little goofy about the grounding but this is crazy...
Well, thanks for the help everyone!!
hi john:
i am working with a Gallien Kruegger which uses this kind of amp module you are using on your project. the problem i got on this is the unit wont come on the sound. if you turn it the unit off suddenly you are listening a portion of the sound until all internal capacitors discharge. for me it was very interesting your post regarding to lower the source AC voltgae so I wanted to do the same test. surprinsingly the unit worked by just only applying 90v AC. then I took out the mechnanical ground to see if it works as your test but it still protecting it if i rise the voltage up to 100V ac. ICE doesnt have an intrernal schematic for disclosure only a block diagram, but this becomes useless for a good troubleshooting. did you detect something else your module that could be the reason why is protecting from this "overvoltage" status. please appreciated your help on this
Hello, sorry, got unsubscribed from this thread...I never found the reason it was only working at 90v and shutting down at 120v. The ground only worked sometime, and not what was causing the issue...it was just that day the it worked that the mains power were lower...
I tried a few things and I ended up putting a series PP cap on the mains to drop voltage and worked fine after that. Weird.
I tried a few things and I ended up putting a series PP cap on the mains to drop voltage and worked fine after that. Weird.
Same problema, no sound at output with thermal and over current ok but enable low (0.2V). I ask some infomation of ICC1 to B&K. Let's se if there is any positive response.
I don't know how the IC detect the undervoltage condition if I know the pin I can trace the part of the circuit but without any information is quite unconvinient.
I don't know how the IC detect the undervoltage condition if I know the pin I can trace the part of the circuit but without any information is quite unconvinient.
Andy - did you ever get information on ICC1? I am hoping to find a datasheet for ICC1 and ICC3 as mentioned here:
ICCx - high power and excellent audio quality for your amplifier.
The topic is a little old, but I finally found what was causing the issue. The problem is with voltage level on 1&2 pins of ICC1, that should be 1.85 and -1.85V, these pins are responsible for overvoltage protection. Voltage level is set by R divider that is located under the white glue at the L401. On my board, one of these resistors was broken. Proper values of resistors for +/-25V are 62k/5k.
I also found some extra documentation:
http://www.audiodesignguide.com/ClassD/Sanyo/LA4930_LV4970_datasheet_r_0_4.pdf
New resistors on my board:
img_20190607_085938753.jpg - Google Drive
I also found some extra documentation:
http://www.audiodesignguide.com/ClassD/Sanyo/LA4930_LV4970_datasheet_r_0_4.pdf
New resistors on my board:
img_20190607_085938753.jpg - Google Drive
Hello Frobek!
I have the same issue with two of this amplifier. The 5K resistor was broken on both amp.
Thank you for your investigation and for your post!
Gabor
Hi everybody, That'Manuel from France
Recently I've got such problem with the gallien-krueger MB115 II bass amplifier of my band bassist. As i'm a electronics engineer i just take a look, and see that the power section is a ICE 50ASX2 BTL . The complete amplifier was mute and the "ready display" around the on/off switch stayed red and quickly i've seen the Enable in/out ( pin 1 on the control connector) was low instead on 5 volts. As in the same time the overcurrent and overtemp out are ok at 5 volts.
Without any schematic it was difficult to find the reason, i've seen also that the inner alarm was also for temp and over /under voltage on the ICE datasheet . I've checked and tested all the passive visible componants except those that were under glue , many thanks to Frobek who gives me the solutions. I've replaced all the resistors under the glue for L401. By 62K and 5.2 K and it works fine. The voltage for alarm is made with 2 dividers connected to -24V and +24 v and as said by Frobek delivered each -1.85 volt and +1,85 Volt.
After looking on the net for long hours i've seen that a lot of people has met the same failure and do not find any solution except replacing the complete assy with about a minimum payement of 75 euros.
I wish that post could help in the futur other users. look at the Frobek picture to locate the failure but surely a major parts of default wome from here.
Recently I've got such problem with the gallien-krueger MB115 II bass amplifier of my band bassist. As i'm a electronics engineer i just take a look, and see that the power section is a ICE 50ASX2 BTL . The complete amplifier was mute and the "ready display" around the on/off switch stayed red and quickly i've seen the Enable in/out ( pin 1 on the control connector) was low instead on 5 volts. As in the same time the overcurrent and overtemp out are ok at 5 volts.
Without any schematic it was difficult to find the reason, i've seen also that the inner alarm was also for temp and over /under voltage on the ICE datasheet . I've checked and tested all the passive visible componants except those that were under glue , many thanks to Frobek who gives me the solutions. I've replaced all the resistors under the glue for L401. By 62K and 5.2 K and it works fine. The voltage for alarm is made with 2 dividers connected to -24V and +24 v and as said by Frobek delivered each -1.85 volt and +1,85 Volt.
After looking on the net for long hours i've seen that a lot of people has met the same failure and do not find any solution except replacing the complete assy with about a minimum payement of 75 euros.
I wish that post could help in the futur other users. look at the Frobek picture to locate the failure but surely a major parts of default wome from here.
Any tips for removing the large coil and silicon? I'm having some difficulty. I've tried a desolder pump and solder wick but can't get the last bit of solder out of the holes and the silicon isn't helping matters when I tried to pull it out of liquid solder bit by bit, didn't budge at all. I tried picking at the silicon a bit but with the coil in the way it's not very easy to remove. Any pointers will be appreciated. Thanks!