Sitech Handpad

[Horwig]

Not sure if this should be here or DIY section.

I have a 10 year old Sitech system on my mount, the handpad conductive plastic keys are getting to be no longer conductive. The good one measure in the low tens of kohms, the bad one many hundreds of K.

Anybody have any experience with ageing conductive plastic? Would a good clean with a suitable solvent remove any surface effect? or would conductive paint make a lasting repair? Have tried surface abrasion, no difference.

Will ask on the Sitech forum as well

 

Huw

[Dr_Ju_ju]

If you want to go down the cleaning route then get some of this, and ONLY this https://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786, I know many BBC studios both radio & TV that rely on it...

[Horwig]

8 hours ago, Dr_Ju_ju said:

If you want to go down the cleaning route then get some of this, and ONLY this https://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786, I know many BBC studios both radio & TV that rely on it...

Thanks Julian, tried switch cleaner, no difference

 

Huw

[Dr_Ju_ju]

How good is your de-soldering & soldering ??  if ok then have a look on Farnell & RS for replacements, in the long run it will probably be easier & more reliable. 

[Horwig]

2 hours ago, Dr_Ju_ju said:

How good is your de-soldering & soldering ??  if ok then have a look on Farnell & RS for replacements, in the long run it will probably be easier & more reliable. 

Yes, soldering is no problem, there is a drawing for a normal switch replacement controller somewhere in the setup manual, might give it a go, but really I would like to buy a replacement plastic moulded element, but now is not a good time to ask Dan or Taj of Sitech, they live(ed) in Oregon, and have had to leave their houses due to the fires

 

Huw

[Tomatobro]

My Brother has this problem with his Sitec hand control and its on the to do list to see what can be done to effect a repair.

I will ask him if he has seen the normal switch replacement drawing (in the manual) so I can build one.

[tomato]

My hand pad is 6 years old and has been in the dome for the last 12 months. I mainly control from the laptop so it has had little use recently and thebuttons have got increasingly intermittent, especially the centre change speed button. I took it apart and cleaned the contacts with alcohol, some dirt (carbon?) came off the conductive pads, and after re-assembly it all works fine now.

I know you have tried this so perhaps the conductive pads do have a finite life. I have sent the info I have on the hand pad to @Tomatobro.

The fires look really bad in Oregon, here’s hoping they all come through safe and unscathed.

[Horwig]

is this the drawing you've got?

[Tomatobro]

I tried to find a circuit diagram before and had no luck. I searched again today and could not find one so it was my intention to take it apart and find out how it worked.

Looking at your drawing its pretty straight forward in that all switches are normally open and the diodes just switch a high/low pattern on the signal wires 1,2,3 and 5. I am assuming that the bridge shown next to the controller (bridges 5v to wire 3) is not really present.

The diodes give the following voltage pattern    (H=5v and L equals Ground pulled low by SiTech)

                                                             1                2              3            5

Right button                                       H               L              L             L

Left button                                         L                H             L             L

Down button                                     L                L              H            L

Up button                                          L               L               L            H

Top left                                              H               H              L              L

Top right                                           L                 L             H              H

Slew/Pan                                          L                H             H              H

 

 

[tomato]

1 hour ago, Horwig said:

is this the drawing you've got?

Yes, that’s it. I’ll take my hand pad over to @Tomatobro’s and let him take a look at it.

[Tomatobro]

I have had a quick look on the net and cannot find a ready built keypad so it looks like one will have to be scratch built using extended button pcb switches. When I have Tomato's keypad I will report back.

[Horwig]

There are posts on the Sitech group where people either buy replacement mouldings, or one where one was sent out FOC.

But I don't want to bother them just at the moment, will use the virtual buttons on the computer for the time being.

 

Huw

[Horwig]

Have just ordered some keyboard repair stuff, will report back if it works

 

Huw

[Tomatobro]

I had a look at Tomato's hand control. Looks to be straight forward to make a tactile switch version so have ordered some parts to make one.

sitech2.bmp Sitech1.bmp

Edited September 21, 2020 by Tomatobro
pics added

[Horwig]

Keypad repair stuff painted on the buttons yesterday, overnight to dry, continuity now about one or two KOhms. Tried in the obsy today, success, but lets see how long the stuff lasts in a cold and damp obsy over winter.

This is the stuff I used:

https://www.ebay.co.uk/itm/Keypad-Fix-Permanently-Repairs-All-Rubber-Keypads-ANDERS/273420633386?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648