Help finish a project....

[neil_kaye]

Ah the humilation of it all, but i know when i am beat. The sad sorry tail is logged here:
Help a noob fix a ZV9
and here:
Help a noob build a ZV9
and i still can't get the one channel to work

I am looking for someone to troubleshoot and finish this project for me. I have spent a great deal of time and not to mention $$$ getting here and to be so close...
I would naturally pay shipping and handling for the one monoblock (both inbound and out bound) as well as for your time. I have several additional JFETS and MOSFETS as well as extra's of all the other components. I recently just rebuilt the board and i am pretty sure everything is good except for maybe a MOSFET and and JFET but than again what do i know

Is there anyone in either the US or Canada (shipping costs) who would be kind enough to lend a hand and help a brother in need.

Feel free to ping me and thanks in advance

Neil

[hifimaker]

Hi Neil,

Perhaps you could give us a brief synposis of the issues or problem you are experiencing? Do you have any test equipment?

-David

[Stuart Easson]

I live in Santa Cruz, work in Palo Alto. I'm happy to help if I can, email me, or turn on your email so I can email you.

Stuart

[neil_kaye]

The short of it is this:
Two of my FET's were groundinng to the chassis... the spark jumping was the dead give away. Pulled them off and tried again, but i was sloppy and tired and don't think i isloated them properly. The channel ran beautifully for about thirty minutes and then pop.
Unable to locate the problem (i only have a digital volt and current meter as testing equipment) i totally restuffed the board.. i even used a new board. This time i was extra careful, went out and bought proper silicone grounding pad (before i was using pices of mica), used plastic screws, re-chedcked all solder joints and then turned on the amp.
Noting, but this time i was not even getting volatge at the V in on the board. Checked the PSU board and noticed that the 4 - 3W resistors had blown. Replaced those and the fuse, turned on the amp. The toried made a load humming sound (i guess to much current was being drawn) and the resistors blew again...
and that pretty much brings you up to date.
Oh, and ho do i turn on my email

[Zen Mod]

Originally posted by neil_kaye
........................
Oh, and ho do i turn on my email

http://www.diyaudio.com/forums/membe...o&userid=59584

click on "user cp" in upper part of page

look for email thingie;it isn't checked by default........(?)


edit:
yes.......

"user cp"......"edit options"........"enable private messaging"......check it

[thomaseliot]

Neil, did you succeed with the second channel?

This is a safe way to insulate mosfets (Aluminium oxide wafers)



and this is for the screw hole

[hifimaker]

If you are using IRF 247 packaged parts than NO insulated washer is needed. I know opinions very, but IMHO the best insulators are the new thermal sil-pads from Bergquest, like Digikey BER178-ND.

They require no grease, look professional when installed, never crack like mica, and have the same thickness from pad to pad, unlike mica.

My amps use to-247 parts for output mosfets, a 4-40 hexhead machine screw, small washer, and no bolt hole insulators. TO-220 parts do require a bolt hole insulator.

Personally I prefer metal hexhead maxhine bolts with a washer on top, with a Sil-Pad. Excellent tight and consistent hold down pressure, clean-not messy, excellence performance.

Here's a link to a picture of the pads as used on my Aleph30 amp.

http://www.diyaudio.com/forums/showt...719#post870719

-David

[thomaseliot]

David, thanks for the Sil-Pad suggestion