Hi
Anyone in / around Abingdon, Oxfordshire who can fit the 2 cables back on to my K40 tube using the correct silicon glue stuff.
Next couple of days ?
Happy to pay of course.
Cheers
Frank
I’m not so far away, in Bedford, and I need to go that direction on Friday. But Abingdon is stuffed with tech specialists, you should be able to find someone closer.
Try oxford hackspace - http://Oxhack.org
@artag
Be really great if you could make it over tomorrow - anytime as I’m at home all day. Tea, biscuits, beer and cash all on offer as I’m desperate to get it working again 
My Mob: 07718 048862
as long as its 100% silicone it will work, and youtube has several great videos about how to reattach the wires to your tube. do not attempt to solder, simply wrap around the stub tightly, use some teflon tape to reinforce it a bit and tie it down, then silicone it. An inch of the water tubing slid over the connector afterwards help further insulate it from arcing to the chassis. just remember to slide it into the wires before you attach to the tube lol
There are replacement instructions on my blog…
+Adrian Godwin can you check the lps IN pin for correct voltage?
OK. I should point out that I haven’t done this procedure before, but I do have 40 years or so of practical experience in the electronics industry and am confident of following Don’s procedure.
Tea, biscuits, and a tenner for petrol ?
Sounds great, thanks very much.
Call or text me for address/postcode.
@artag @Frank_Farrant Kinda like a K40 “reality show” episode! 
Mixed success today.
The original tube was soldered at the HV end, twisted wire at the LV end. I soldered the LV end OK but the HV end wouldn’t take the solder (and I did use ‘proper’ lead solder with a nice strong rosin flux). It seemed to take eventually, with the help of some TC wire wrapped around the post, but when tested it arced badly.
I’m hoping that allowing some time for the silicone to set properly will help, but it may need another go.
Don, I couldn’t test the control voltage as I was only blipping the laser on - arcing was too bad to leave it while I fiddled with a DVM.
The silicone (a 703 clone from china that came with my cutter) was really thin and slippery. It made it difficult to keep the silicone tube in place.
I guess it would be better to silicone the joint, let it set, then add the tubing with a touch more silicone. But I couldn’t stay 24 hours for it to set
@artag it was soldered on the tube end? I did not think that the anode would take solder that is why its usually wrapped and then encased in silicon.
Did you wrap it then slide silicon tubing over it followed by filling it with silicon.
When you “blipped” it on did the tube light up?
@Frank_Farrant can you post a picture of the supply, or did you in another post I forgot.
Frank had already swapped the tubes, so I didn’t look at the old one. But the anode wire had residual solder whilst the cathode wire had clearly only been wrapped.
I’m pretty sure the tube lit - it was hard to be sure as the arc around the anode was loud and bright so I didn’t want to examine carefully. But I definitely got an impression of a pink line.
In both cases I cleaned and attempted to tin the pin, then wrapped a little stranded wire around it, soldered that to the tinning, then soldered the lpsu wire to the solder blob. This worked well on the cathode - I had successfully got some solder to take on the end of the pin - but I was less sure about the anode. I couldn’t get the previously tinned HV wire to link firmly to the pin, but the wrap of stranded wire seemed firm.
Re Joe’s comment - the stranded ground wire was full of silicone in the strands that had been wound around the pin. It’s not like a proper gas-tight wire-wrap connection - I think there’s a fair chance that silicone could creep under the entire connection and insulate it, so I’m much happier soldering it, even if it’s just to a closely-fitting wrap of wire. Maybe a better approach would be to wrap it, heatshrink it, then silicone & tube it to add an insulating layer.
I’m wondering why they don’t use a spring contact (a female connector pin) strengthened with heatshrink and then surrounded in silicone.
@donkjr Do you need a picture of the PS ? If so, what part(s) ?
@artag Thanks for coming over. Appreciate it. The silicone feels set, but I won’t test again until the morning.
@Frank_Farrant Just a photo of the supply from the front showing the connectors.
Can you summarize where you are with this repair now?
To date summary?
…Replaced a LPS
…Replaced a laser
…You have a digital control panel
Problem at the moment is severe arcing around the anode. I’m aware this can damage the lpsu so don’t want to leave it on whilst investigating - prefer to do a possible fix and then a brief test.
The digital control panel is more advanced than ones I’ve seen before : it has a load of buttons marked +1%, +10% etc.
Like this :
https://www.alibaba.com/product-detail/k40-laser_60658285211.html
@donkjr Laser stopped working 2 weeks ago and China Techy said it was the tube, so I bought a new tube ( next day from Amazon ) and put it in the unit.
China Techy then asked me to do a test on the PS by shorting out 2 wires at the front. I did this and he said its the PS at fault. Shipped me a new PS and that arrived the other day.
Then I messaged here to ask for help connecting the 2 cables to the Tube.
.
Both wires attached yesterday by soldering and silicone, which I allowed to set overnight, but when I pressed Test button on K40 today, I still get a loud noise and Arcing.
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@donkjr Pictures to follow shortly.
I am really dependant on the machine, which I realise is stupid, but I need to get it working.
.
Should I post another request for urgent help ? I’d also like to borrow a K40 from someone locally if possible ?
