Anybody build their Gristleizer yet, comments on it?

[tangerine]

Thanks for the reply.

That's a lot of stuff to get through and I have a visitor coming for the weekend so I might just wait until they have gone rather than try to rush through it before they get here; likewise with the previous reply.

Anyway, I am not completely despondent now.

Thanks again.

[tangerine]

further - power off, pull the IC1 if socketed, then measure the resistance between pins 8 and 9 as you switch the rotary switch. list results. then measure between pin 8 and the "3" lug [clockwise?] of the depth pot as you switch work. list results.

I hope I'm looking at the right circuit diagram.

I had a few minutes so I did the measurements you suggested. I did two for the pin 8 to lug 3 of the depth pot, one fully CCW and one fully CW:

Pin 8 to pin 9

Position 1 = 1.0MΩ
Position 2 = 1.2MΩ
Position 3 = 0.9MΩ
Position 4 = 1.8MΩ

Pin 8 to depth pot lug 3

CCW
Position 1 = 1.1MΩ
Position 2 = 0.9MΩ
Position 3 = 0.9MΩ
Position 4 = 0.9MΩ

CW
Position 1 = 0.9MΩ
Position 2 = 0.9MΩ
Position 3 = 0.9MΩ
Position 4 = 1.1MΩ

[duck_arse]

Code Select Expand

Pin 8 to pin 9

Position 1 = 1.0MΩ
Position 2 = 1.2MΩ
Position 3 = 0.9MΩ
Position 4 = 1.8MΩ

this shows your switch is all wrong, I think. from the circuit I'm looking at, you should have 47k, 47k, 180k and 96k, near enuff.

measures to the pot "lug 3" [as shown on the dia] should be 100k, 0R, 0R, 47k.

the pdf I'm looking at has "draft 16.04.2007" - does this conform to the board still? can someone point me to a more correcter document, please?

[tangerine]

That's what the diagram I have says.

[tangerine]

I really have to wrap things up for the weekend shortly as I don't like having things lying around in pieces when there are people here but I thought I'd upload a couple of pictures which might show where I am at.

These are my best autopsy photos:

[bluebunny]

Also, one of the ICs supplied was not as specified, the MAX1044 seems to have been substituted with an IC identified:

7660S
CPA2
L901AAN

I don't know much about ICs but the notes say that if any other IC is used to disconnect pin 1 and I have tried it with pin 1 both connected and disconnected.

I don't think the instructions to lift pin 1 are strictly accurate.  It's probably true if you were to use an LT1054 in place of the MAX1044, but not the ICL7660S that you've got.  Put pin 1 back in its socket.

Not sure how this relates to your other issues, though.

[duck_arse]

was your rotary switch pre-wired, or did you wire it yourself?

[tangerine]

I put pin 1 of the IC back in.

I wired the switch and everything else myself.

I may have done it incorrectly but in my defence, this is the image from the instructions along with the pin layout of the actual switch which was supplied. The instructions show a switch which seems to be divided into three sections with the connectors in two of them. I tested the connections on the switch before I did any soldering to try to figure out how it I though it should be connected given that the switching mechanism connected opposite pins via the corresponding central pin (in a similar, though obviously different way, that an imported Stratocaster 5-way switch works). If I didn't follow this train of thought, then I couldn't see how the switch could work as there would be open circuits.

I won't be able to do anything else on the actual pedal until tomorrow, though.

[duck_arse]

orright. I see your switch is wired to a plug, so pull it out and we will probe the switch.
if I'm seeing your photos correctly, you have orange as one common and black as another common. set your meter to ohms, wind the switch shaft all the way, let's say, anticlockwise, put one probe to the orange pin in the plug, and then probe the other plug-pins to find what other colour is connecting. write down that colour.

step the switch one position clockwise, probe the pins again and find what colour is now connecting to the orange. write down the colour, step the switch, probe, write, step, probe, write. if the meter doesn't show low, low low ohms at some pin each time, write down O/C instead.

then move your stayput probe to the black wires pin [if that's your other common connection colour] and probe to find what is connecting. write down that colour [or the dreaded N/C] and step the switch. etc etc etc.

then tell us the results, please.

[tangerine]

I kind of already did this test and the colouring of the wiring I chose was to reflect the results of the test I did on the plug.

So, before I connected any wires to the plug, and having tested to get a rough idea of which pins seemed to be doing what, I shorted out the two common pins and then tested the diagonally opposite pins, all of which gave 0Ω whilst checking that there was no connection, accidental or otherwise, to any other pin.

So, you will see that in the photo the plug is wired as follows with each colour wire being connected to the same colour opposite, if that makes sense; so if yellow on the red side is connected to the pin at, say, 3 o'clock, the yellow on the black side is connected to the pin at 9 o'clock.

Red (common)
Blue
Green
Yellow
White

Black (common)
Blue
Green
Yellow
White

I have then retested the connections back as far as the plug soldering on the back of the circuit board.

Anyway, although I knew the results because it is wired up that way by design, I just checked again to be certain - so they are as follows:

From fully CCW and corresponding to the plug colouring (above) for both sides, black and red:

Position 1 - Blue - 0Ω
Position 2 - Green - 0Ω
Position 3 - White - 0Ω
Position 4 - Yellow - 0Ω
Position 5 - VOID
Position 6 - VOID

Just to clarify also, I tested for shorts.

By the way, if you are wondering about my choice of wire colour, I wasn't sure where this was going to lead me and I generally use red for positive/signal/live and black for negative/earth and these were the only colours I had left apart from brown which I only ever use as a substitute for black.

[duck_arse]

referring to the "draft" pdf circuit - my next step would be to pull the switch plug and the IC's out, and then probe the socket for the TL074, to find which IC pin connects to the switch common on the connector for SW2A, and which IC pins connect to the positions 2 and 3 of SW2B. I'm groping in the dark somewhat, not having the board layout or any part numberings to go by.

while the IC is out, I'd be testing resistance between pins 8 & 9, 12 & 14, 1 & 12, 1 & 2 and between 3 and ground, 13 and ground, and 19 and ground. and the pins of the unused opamp section, see where/how/what they were connected.

just for my own peace of mind - when you say "I shorted out the two common pins", you don't mean you shorted the two pins to each other, do you? you need to test each common to its own throws. is there any chance you can show us the top part of the rotary? is there a position lock-out washer on those switches?

[tangerine]

Just a quick reply to answer your last question, yes, I shorted out the two centre pins whilst testing the switch. It saves testing the pins twice, if you think about it.

(Position 1Red > Red > Black > Position 1Black) tests (Position 1Red > Red) and (Black to Position 1Black) simultaneously.

There is no visible way to adjust the switch to block out the void positions as it is locked by a bent tab which is cut out from the plate on the top of the switch.

[duck_arse]

ahh. well, first - no no no, NO, NO. you test one common and look for the connections it makes. then you test the other common, and seek its connections. don't don't don't short the two sections of switch at the commons. and, you probably should try remove the nuts and washers and lock-tab washer, rotate the switch fully CCW (without the stop fitted) and only then refit the stop washer at the 4 position. then rotate the switch to make triple double sure you've got four positions.

and then - retest your commons against their connections.

[tangerine]

Consider that done.

The test I did goes beyond that but I'm not going to argue about it.

There is no way to adjust the stops on the switch. The only removable parts are the nut and washer for installation into the enclosure and they reveal nothing. There is no way to access the stop without destroying the switch. Maybe it is a cheap switch.

[duck_arse]

ahh, sorry, I misread your comment about the bent tab. carry on, tally ho, good luck!

[tangerine]

I've ordered a DP4T switch so that if I ever get it working, I won't have two null positions.

[tangerine]

I ordered two DP4T switches and two DP6T switches arrived!

I'm now waiting for the correct replacements.

[duck_arse]

is this the type switches you ordered/expected? I'm waiting for some of these as well, for a pair of other projects.

[tangerine]

No, I ordered a rotary DP4T switch to replace the DP6T switch which came with my Gristleizer kit and it looks the same as the one in my earlier post apart from the number of pins.

[duck_arse]

gotcha. good luck.