Babelfish M25, SissySIT - general building tips and tricks

[Zen Mod]

replace pcb (one previosuly mounted) and replace SIT

later test them both , once when you have one functioning amplifier

 

[cal3713]

Will do. Probably next Tuesday or Thursday. Really looking forward to hearing the amps. So close.

 

[Zen Mod]

have to wait 'till next Thursday , to get newly made mains NTC pcbs

bummer

 

[chromenuts]

Fugly

 

[dBel84]

Looking great, I love the way that the heatsinks came together.. dB

 

[ItsAllInMyHead]

Great looking build as always, ZM!

 

[Zen Mod]

...... to get newly made mains NTC pcbs

.....

ha, it took me at least 5yrs , to engage brain and draw them ....... ordering is trivial afterwards

 

[mcgillroy]

have to wait 'till next Thursday , to get newly made mains NTC pcbs

bummer

Like those heatsinks - where did you get these?

 

[brianco]

I'd be proud to have that!!!

What is the physical weight of this amp???? [ ???]

 

[Zen Mod]

it's nothing else than new guts in old amp - it was Papa's Koan (M)2 , amp for living room

more in my blog Papa’s Koan (M)2 , an amp for living room | Zen Mod Blog

it was heavy as on pic , now few kg more

 

[dewdrop]

ZM, do you recommend mounting the PCB to the heatsink or the riser plate is fine? Need to know the rise dimensions to cut to. Thanks in advance

 

[Zen Mod]

please clarify

simple way of mounting you can see on start of the thread , and later

you can also use L or T bracket

so , I need clarification what you mean with "riser"

 

[dewdrop]

Sorry bad choice of words, i mean L bracket.

 

[Zen Mod]

will write tomorrow

now half sleeping , so better to avoid any measurements .....

 

[cal3713]

Well, finally got back to it. Pulled my non-working board as recommended. Not sure, but I think I might have over heated a part...

 

[cal3713]

So glad I have two sets of boards...

 

[Zen Mod]

that's SMD 100nF-200nF , filter cap for 7805

if you're able , you can solder any small 100nF cap there , on SMD pads

it couldn't go Dodo because of overheat (nothing is heating it) , neither you have critical voltage

maybe you got blob or splash of solder there which did go Puf! , taking cap with it

worth trying to troubleshoot , minding is there steady 5V at 7805 output

if yes , hall chips are alive

 

[cal3713]

that's SMD 100nF-200nF , filter cap for 7805

if you're able , you can solder any small 100nF cap there , on SMD pads

it couldn't go Dodo because of overheat (nothing is heating it) , neither you have critical voltage

maybe you got blob or splash of solder there which did go Puf! , taking cap with it

worth trying to troubleshoot , minding is there steady 5V at 7805 output

if yes , hall chips are alive

So, replace blown/melted filter cap, reinstall board, reconnect SIT, and measure voltage difference between p2 (ground) and p3 (output) of 7805? That should be 5V.

I can leave input and outputs unconnected during the procedure, right?

Thanks ZM.

 

[Zen Mod]

pretty much like that

in fact , no need for mounting pcb at all , for 5V check

you can leave mosfet in and no SIT , just temporary short pins 3 and 4 of opto , with thin wire

if you have some nice 7-8-12V PSU , connect just that to GND and positive rail , and check 7805

 

[Zen Mod]

got NTC pcbs today


LEDs , tiny input wires , final cooking ........ then rocking!