Pars

Happy Birthday to both of you!

I'm certainly no expert, but the production kgsshv schematic I have shows a pair of 1k resistors R3/R4 feeding the bases of Q1/Q2 (2sc4686a). 180R resistors (R5/R6) hang off the emitters of Q3/Q4 (2sc4686a). Not sure if the 1K resistors you are seeing are R3 and R4 in the schematic? If so and if the current boards match the schematic I have, you don't want to jumper them. Hopefully Birgir or Kevin or someone else more knowledgeable will weigh in here

Happy Birthday Vicki! I second/third/fourth the above on missing your presence around here.

Shouldn't the board layout be fixed to allow the Molex connector to be used? Better connector (locking) than the simple 3M one.

That is massively OCD close enough on output voltage BTW, your meter seems to be missing a knob

Thanks Kevin! At first I did a WTF with the 3 bridges until I figured out why

No, I was referring to the published BOM. I figured leaded caps would work fine for the 4700uf. This is what I think I will use: LGU1H472MELZ and EEU-FM1H221 Silmics are good caps in my experience, so I may just use the Silmic that is spec'd in the BOM.

For the GR LV board (not sure if this applies to the HV as well), I'm not sure why "audio grade" electrolytics were chosen for the 220uf and 4700uf caps (Elna Silmic and Nichicon KS) with 85ºC rating instead of long life higher temp 105ºC caps? Measuring for the 220uf cap, the board allows up to 10mm diameter with 5mm LS. For the 4700uf cap, up to 25mm diameter with 10mm LS (snap-in, though leaded could probably be used).

Thanks. I had figured the 1N4007s were there to protect something, but hadn't ohmed or traced them out yet. And "DOH" on the LED/2K resistors Kevin had noted an updated schematic, but what I see in the schematic posted previously still shows mj15024/15025 TO-3 devices, no protect diodes, etc.

Sorry to hear about your classmate Wayne. RIP. Sad story...

Link the same as the previous? EDIT: Also, a couple of questions: 1) The 1N4007 diodes are not shown in the schematic. Could I use 1N4001/4002 here (have them on hand)? I'll trace them out on the board to figure out where they are, unless they are in the updated schematic. 2) The 2K resistors (R13/R14) and the LED between the + and - output: what is their purpose? I noticed that Kevin had not put the LED in, and others completed boards as well were missing these. A dummy load for testing?

Looks nice Marshall! Good ride?

Yep, that gave me a chuckle this morning

Best thread title evah (IMHO)...

Who is Bascom King? Never heard of him... apparently has/had something to do with Infinity?

NPN MOSFETS? Heh...

In the 4th pic, the TO220 C4686 in the center doesn't look like it is soldered. Soldering on some of the radial 100K resistors looks suspect also.

I just recall the wet tantalums back in the '80s would blow'd up real good, bubba And start on fire, with silver shit coming out of them. Generated a distrust in them, to say the least.

Big enough tip on your iron (3.2mm is what I have) and a good soldersucker, something like this Edsyn Soldapullt I got mine at Frys.

I've noticed that the BOM for this, as well as for some of the KGSSHV Carbon stuff, uses large value tantalum caps (47uf/25V), for which there are also ceramic MLCC X7R alternatives available. Any reason for using the tantalums as it would seem that the ceramics would have advantages, price being one of them? For example the tantalum 47uf 25V 581-TAP476K025CCS @$3.13 could be replaced with a Murata 81-RDEC71E476MWK1C3B @$2.13 MLCC ceramic. Just curious...

Happy Birthday!

Happy Birthday!

The input wiring is more susceptible to noise than the output wiring as the signal levels are lower. Having the RK50 at the rear keeps the input wiring shorter, so theoretically should be better. Mouser does have cable hold downs like you pictured. http://www.mouser.com/Search/Refine.aspx?Keyword=644-CCH12-S10-M

Happy Birthday Jim!

Could you use something like a dental pick in the screw holes to pry behind the driver frame? You can usually pick these up cheap at hardware stores like Ace, etc.