Service (Maintenance, Troubleshooting) on PWM Class-D (Class-T) Power Amplifier Stages - which Papers, Documents and Books ?

[tiefbassuebertr]

Troubleshooting on PWM/Class-D Power Amplifier Stages - which Publications are released ?

concerning not digital amplifiers like tube and solid state single ended and push pull class A/AB there are a lot of publications available - e. g.:
https://sound-au.com/troubleshooting.htm
https://www.allaboutcircuits.com/worksheets/bjt-amplifier-troubleshooting/
https://www.google.de/books/edition...ier+Repair+service&pg=PA1&printsec=frontcover
https://www.google.de/books/edition..._Guitar_and_Amp_Mai/FCaskxpGLooC?hl=de&gbpv=0

Concerning Class-D resp. PWM power amplifier stages I just found only publications regarding the basic operation and special circuitry features, but not regarding service and maintenance/troubleshooting - go to this URL's:
https://www.soundandvision.com/content/bruno-putzeys-head-class-d
https://books.google.de/books?id=sF...=gbs_selected_pages&cad=2#v=onepage&q&f=false
https://ieeexplore.ieee.org/document/954289
https://www.allaboutcircuits.com/projects/how-to-build-a-class-d-power-amplifier/
https://www.semanticscholar.org/pap...g-Ge/e5adc785ac9fdfbd546e7bad725a6cb5fcadc341
https://www.semanticscholar.org/pap...-Wei/1b37a348f7a5418b7fe62394ce9bf28c22685b13
https://www.analog.com/en/analog-dialogue/articles/class-d-audio-amplifiers.html (go for an overview to last page)
https://forum.visaton.de/forum/mess...uben-ein-korrekturprogramm-würde-alles-regeln
https://web.archive.org/web/2020112...ion-bruno-putzeys-purifi-hypex-kii-mola-mola/
https://www.audiosciencereview.com/forum/index.php?threads/interview-with-bruno-putzey.14970/
https://www.diyaudio.com/community/...n-a-decent-book-on-class-d-amp-design.196068/ (closed thread)

what is the reason therefore ?
Maybe confidential details (B&O, Hypex and most other manufacturers always explain the same: ""No User Serviceable Parts Inside") ?

For this reason the complete class D main board resp. module is in general to replace on power amplifier devices in case if occur any failures/issues.

P.S.: why is this thread closed resp. inactive ?
https://www.diyaudio.com/community/...amplifier-books-overview-google-books.153311/

 

[NareshBrd]

Most Class D power output chips are soldered to the PCB with extra large pads, those are difficult to service.
The extra large pad conducts heat to one dedicated layer in the PCB.
See the data sheets for examples.

And the chips are pretty reliable, modules are cheap, why bother?
Removing the chip without damaging the board is itself a hassle.
Replacing it is even bigger hassle.

And most of the other components are SMD, the boards are assembled on lines with pick and place equipment, and test jigs. Wave soldering is normal.
Getting exact replacements is also an issue, SMD rework is a special skill.
If you do it yourself, fine, but at times the labor cost alone equals that of a new board...

So, please understand these limitations, and post your opinion.

 

[tiefbassuebertr]

You are absolutely right concerning IC-units like in image No1-2, that's looks like more than a smartphone main board like in image No 3, because for repair such units appropriate soldering devices like explain from Dr. Bias.com - e. g. under

are absolutely necessary

My question related mainly to expensive modules in discrete version without ICs or quasi-discrete version with standard ICs as you will find from image No 4 onwards.
check also images under
https://www.diyaudio.com/community/...ed-in-a-lot-of-models-from-harman-jbl.288080/

 

[NareshBrd]

You still need a scope and a lot of equipment to find the fault.
Parts?
Try finding a spare display for a 5 year old phone.
These are more or less disposable / non-repairable units.