FrankenZERO - A bang for buck exploration with a DIY Heart ! - Page 10

Well I've given up trying to rescue my DAC board for now, without a schematic or a working one for reference its very difficult to try and find my problem. I don't know if I have something open where it should be closed, or if I ended up with a short somewhere.

I have a new DAC board on the way to me from china, so I may check my old one against the new one, and then debate if I want to try the full mod again, or try just adding the bypass caps to the stock electrolytics. The risk of damage would be low there.

Anyway, I got 1 Alps pot from Kingwa dun know whether can be used or not or is it good.

Looks like I have to wait another 250 hours, before fully run in.

It looks the high and low is a little compressed, though the tube amp buffer uncompress it.

I will try to get 1uF green sausage to test.

My Mullard 12AX7 reissue and 4xtungsol 6v6GT is also on the way. hope to do away the buffer and see how it goes.

I had some problems with the diode replacement, but they all have continuity to the board and I double-checked their orientation. I still think the main problem was at the big power supply caps. I had installed the new ones with the polarity reversed, but caught my mistake before any power had been applied. When I removed and reinstalled them in the correct orientation I damaged the solder pads, one broke off completely on the bottom side of the board, Probably because I was being impatient, and I'm used to working with pcbs that have the holes thru-plated with heavy copper. A couple of the holes got to looking pretty ugly after repeated attempts to resolder after it didn't work the first time, I would be embarrased for anyone to see the carnage

I scratched off some of the solder mask at the damaged solder pad and filled the gap between the cap leg and the trace with solder, and I noticed that leg had a trace on the top side that lead to one of the yellow film caps so I added a jumper wire there since I wasn't getting any continuity between them w/o the jumper.

I was pretty confident I could do this mod no problem, I've built several speaker amps and my Millet SS, so I was actually surprised and very disappointed when it didn't work. The Zero still puts out some sound, albeit very weak, and the headphone section cuts in and out depending on where the volume pot is, which confused me also.

I have a Fluke 87 DMM left over from when I worked as an auto mechanic, I know I have continuity from all the components I replaced on the bottom side of the board, at least from what I could see by just trying to follow the traces, but I could be missing something on the top layer, IDK for sure. Hopefully having a good board to compare to will help me find the problem.

One other thing I thought of is that while I was removing the board one of the times I accidentally let the side of my iron melt one of the relays a tiny bit that I'm guessing are for the headamp, don't know if that would cause any of my symptoms. I had already replaced the stock RCAs with the cardas ones I had so I needed to desolder the wires going to the new jacks when I did that. Another mistake on my personal wall of shame with this project, haha

Kit arrived!

Hi Peete,
Received the Mod kit today! What size shrink wrap do I need to order?

Did 2 parts of the mod but left the heavy stuff for my next day off. I did the HDAM cap mod and the Headamp section. Headamp section was easier than the HDAM because whoever built the HDAM put globs of solder on the little white cap leads so I had to be very carefull not to bridge it to the point next to it. I finished it in 2 hours and so far so good. I powered it up and no shorts, no static (knock on wood). Im still a noob so a little nervous with all this.

Its a pain to fit it back in the case with the cap hanging off of the back and raised a little but I got it to fit.

Thanks again for all the help guys. Ill report back when the next section is complete.

Soldering advice

Hi,
I had some problems doing the little resister swap out today for the LED Brightness. Because the thru holes are not "ringed" like I'm used to working with it seems difficult to desolder and then with no ring surface difficult to resolder. However, it's real easy to pull up a trace! Any technique suggestions and where most of the difficulty will be?

Thanx!

I share your pain, hehe. I don't really have good technique myself with these boards, they are more fragile than I am used to working with too. Best bet is to take your time and be careful, hopefully I will do better on attempt number 2

Edit- Also PP I know what you are talking about with the ship times from eastern block countries. I am still waiting on a shipment of .22uf k42 caps that I bought on October 24th...
I contacted the seller (KWTubes, seems like a nice guy) and he figured they must have been lost in shipment somewhere, so he sent me another pack over a week ago that I am hoping shows up, he even said if the first package does ever arrive to just keep them both. I've gotten other caps from him in a reasonable amount of time, he's in Lithuania.

Thats why I needed pics to verify the correct position. Nowhere in the threads or pictures does it show the box caps removed. Also in the pics posted the Cap leads are soldered to the box cap spots but underneath.

http://www.head-fi.org/forums/attach...s-cap-hdam.jpg

By leaving the box caps on am I affecting the sound in any way? Does this nullify some of the benefits of the PIO caps and Frankenmod?

deleted

does anyone know of a seller who sells the zero dac board seperatley? I might have fried mine. also can you replace a lifted pad with a ring made of clipped leads? in other words will the solder and ring continue the circuit?