Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Dr. Soot on March 10, 2023, 05:31:31 AM

Title: Speedball install voltage issues [resolved]
Post by: Dr. Soot on March 10, 2023, 05:31:31 AM
Hi all, I am in the process of installing the Speedball upgrade.  I just finished installing the first board and went through my voltage checks.  Here are the results;

OA -184 V
IA - 185 V
B-A/B - 0 V
IB - 185 V
OB - 184 V

OA and OB should be half of the voltage I am reading.  I followed the flow chart and determined that the 12AU7 does glow, but the LEDs on the bottom of the 9 pin socket do NOT glow.  I went over each of the solder points on the 9 pin socket to make sure they were OK, and they appear to be.

Any help is much appreciated.  Happy to upload some photos, just not sure what to take a photo of.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 05:34:32 AM
Can you post photos of the top and bottom of the small PC board?

I would expect that you don't have the center legs of the MJE350s well soldered. If your 12AU7 glows, it would be very important to leave the LEDs on the 9 pin socket alone.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 05:46:22 AM
Here you go.
Title: Re: Speedball install voltage issues
Post by: Doc B. on March 10, 2023, 06:01:28 AM
Look at the center leg of each MJE350 on the top side of the
PC board photo. There needs to be solder between the leg and the solder pad. Watch this starting at about 36:05  -

https://youtu.be/EN16Pi7pcfk
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 06:08:09 AM
Many thanks Doc. I will follow up if that works.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 06:17:22 AM
Still getting a voltage in the mid 180's at OA and OB.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 06:18:59 AM
Can you carefully measure the voltages at A3 and A8?  Can you repost the photos of that board?

Also keep in mind that if you try to just add solder from the other side of the board rather than reheating the joints from the bottom, you are unlikely to resolve the issue (I just mention this because we have seen it happen a bunch).
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 06:21:17 AM
OK, will make sure the board is properly soldered and then I will take photos and measure A3 and A8.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 06:37:09 AM
A3 = 180.6 V
A8 = 182.2 V
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 06:49:12 AM
A3 and A8 are pins on the 9 pin socket.  You would be the first person in the history of the Crack to measure voltages like that at those pins...

Could you remove that board again and post photos of your stock Crack build without it?
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 06:53:30 AM
I assume the Crack should be plugged in for these measurements, correct?
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 06:56:50 AM
Yes, you should not get any DC voltage without the amp plugged into the wall and powered up.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 07:02:12 AM
ok, here are photos of the 9 pin socket and the stock build

Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 07:03:44 AM
Could I see an overhead of the whole build?

A4 and A5 don't look well soldered.

If you have 180V at A3 and A8, then I would be very, very surprised if your stock build functioned properly and passed its original voltage checks.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 07:06:21 AM
When you say you want to see overhead, you mean right side up?  It worked fine for the last year plus that I have had it.  I will resolder all the pins on the 9 pin socket.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 07:12:34 AM
I'm interested in seeing the same shot that's on page 46 of the build manual.

If your Crack was functional for that long, please recheck the voltages at terminals A3 and A8.  If they are that high, can you check where the black wires meet at the headphone jack to be sure one isn't loose.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 07:43:27 AM
here you go

A1 = 184.7 v
A2 = 169.6 V
A3 = 180.9 V
A4 = 0 V
A5 = 0 V
A6 = 184.1 V
A7 = 169.8 V
A8 = 174.5 V
A9 = 0 V

@ the headphone jack

Red = 168.0 V
White = 168.6 V
Black = 169.9 V

Not sure if all of those are helpful, but figured I would add them just in case. 
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 10:46:21 AM
Put the 22.1K resistors back and remeasure your voltages.

Are you sure you aren't seeing mV instead of V? 

Which terminal are you using as a ground reference?

When we see a set of voltages like this that are impossible, generally it's a loose, missing, or broken black wire.

Also do be aware that the Alps Blue pot is designed to be installed onto a PC board, and soldering wires directly to those pins will often cause the pins to snap off.  You can buy mounting PC boards for a few bucks on eBay.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 10, 2023, 12:13:46 PM
I cannot find the 22.1K resistors since removing them.  Can you suggest a place for me to purchase them, perhaps the item specs so I can get the correct ones?

I am using 12 as the grounding terminal.

A3 = 183.1 V (see photo)

A8 = 178.4 V (see photo)

Other random voltage measurements

18 = 97 V
20 = 0 V
14 = 0 V
Center of 9 pin socket = 172.4 V

On the pot... (see attached photo for pot labels)
Ground top row = 172.4 V
Ground bottom row = 0 V

Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 10, 2023, 02:10:26 PM
The ground lugs on the pot are connected with a piece of wire to terminal 12.  Since you have 180V between those two points, there is a discontinuity in your black ground wire that is causing your amp to not work properly.  As I suggested before, it's extremely common to find this exact issue where the two black wires connect to the headphone jack, and commonly one will not be captured by solder.

From what you are showing, we can be 10000% sure that you have a loose/poorly soldered black wire in your stock build that has nothing to do with the Speedball installation (other than likely being disturbed in the process of fitting that first PC board).

There are only a small handful of solder joints on the ground bus, why not reheat them all?   That would be terminal 3, the junction of the black wires on the HP jack, terminal 12, terminal 14, and terminal 20. 
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 11, 2023, 05:11:19 AM
Thank you for all the help. I finally found the poorly soldered joint on the pot, it was one of the ground wires.  I have since repaired that but was still getting some goofy numbers and started trouble shooting all the solder joints on the 9 pin socket.  I accidentally ended up breaking one of the LEDs (the one at A3) and replaced it with one from the Speedball kit.  That fixed that.  I am still getting about twice the voltage I should be getting at A1 and A6.  I believe it is probably an issue at the pot.  And your suggestion about putting the pot on a breadboard was something I had actually done but for whatever reason, swapped the pot for one without the breadboard.  I have another couple pots, I will put one on a breadboard and go from there.  Again, thank you for all the help.  You guys are awesome.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 11, 2023, 05:27:33 AM
Can you please repost the voltages at terminals 1-5?
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 11, 2023, 06:01:19 AM
Voltages

1 = 73.9V (seems to have fixed itself or I just mis-measured before)
2 = 0 V
3 = 0 V
4 = 176.7 V
5 = 166.7 V

A1 = 167.6 V
A2 = 0 V
A3 = 1.634 V
A4 = 0 V
A5 = 0 V
A6 = 72.5 V
A7 = 0 V
A8 = 1.576 V
A9 = 0 V

The A3 and A8 LED now glow (they didn't before) but on the Speedball breadboard, only the LED closest to the 1B connection glows.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 11, 2023, 08:22:46 AM
Well half of your Speedball is working at least.  I would expect at least two lit LEDs on the front PC board. The higher than expected voltage at A3 tells us that the half of the C4S feeding A1 is likely attempting to source too much current.   It would be a good idea to see some more photos of the PC board itself, especially the bottom.  You can also remove the wires at IA, OA, IB, and OB, then rotate the board 180 degrees and hook it back up.  If that high voltage moves to terminal 1, then you know you have an issue to deal with on that half of the PC board.

The voltages you posted now show that you do not have the voltage issue you had before.  If you didn't do anything specific to resolve the issue, then you are still going to have to find the loose wire/flaky solder joint causing this issue.

Ultimately I would still suggest finding a pair of 22K/1W resistors just in case, because it's more difficult to debug stock Crack issues once the Speedball is installed.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 11, 2023, 08:33:52 AM
Thanks for the suggestions.  I did resolder the connections on the pot and on the 9 pin, that is when I saw the voltage correction.  I am reasonably confident that solved that issue.  I will do what you suggest on the PC board.  I am sure I just didn't solder well.  I don't have the best vision and even though I use magnifying glasses and whatever else I can use, it still isn't that clear.  I am attaching images of the underside of the PC board.  I may desolder and desolder it all, not sure.  But once again, thank you for all your help.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 11, 2023, 08:40:19 AM
This is likely your problem.  These two pads need to not touch.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 11, 2023, 01:03:08 PM
I took care of that solder bridge but have been following all the lines to see check all the connections and currently, I find that OB reads about 10-11 V and I cannot pinpoint the where the voltage drop occurs.  At this point, I am almost re-soldered every connection.  I just may give up and buy a new kit and do it better the second time.  I assume 120 V is coming in and the transformer and at some point, I am getting about 230 V.  I need to check the jumper wire between 14 and 16 on the transformer to make sure it is OK. But I don't think that would explain the voltage drop across the speedball board.  I would assume if I am getting 74 V at at OA and then read about 10.5 V at OB, something must be wrong on the board, not necessarily the crack itself.  Anyway, any chance I can buy a few parts of the speedball and not the whole thing?  Just the one board I have built so far and try again.
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 11, 2023, 03:24:50 PM
Leaded solder and more heat will be really helpful.  You can contact replacementparts(at)bottlehead(dot)com regarding purchasing a new front PC board and electronics.
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 12, 2023, 01:43:36 AM
I am using Quad Eutectic Solder with rosin core and I have my solder set to 675 F.  Should I use different solder and go hotter?
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 12, 2023, 06:04:45 AM
Way, way hotter. 
Title: Re: Speedball install voltage issues
Post by: Dr. Soot on March 15, 2023, 02:54:31 PM
Reheated the solder points on the breadboard at a 800 F and here are my results:

OA - 72.6 V
IO - 181.5 V
B-A/B - 0 V
IB - 181.8 V
OB - 71.9 V

So I think I have got that working well.

I have to wait until the new LEDs come in to finish the second board since I broke one LED earlier.

Also, I put a new Alps Blue volume pot on a small breadboard to clean that up.  Can you please tell me the gauge of the solid core wire used to wire up the volume pot to the headphone jacks?  I'm guessing somewhere between 26-20 gauge, but I want to buy the correct wire.

Thanks again for all your help.

Pedro
Title: Re: Speedball install voltage issues
Post by: Paul Birkeland on March 15, 2023, 04:03:00 PM
20 AWG solid core would be consistent with what we provide.  Be sure not to get stranded wire!
Title: Re: Speedball install voltage issues [resolved]
Post by: Dr. Soot on March 15, 2023, 04:15:33 PM
Thank you!