Keithley 2701 Broken plastic - Page 1
Forum section: electronics / repair

author: tombi
author_rank: Regular Contributor
timestamp: October 22, 2014, 03:16:12 am
content: Hello,I had so much fun repairing this old Tektronix 475 scope I started a new project! A broken Keithley 2701!Unfortunately it actually wasn't that broken (not electronically). The front has had a knock which pulled the plastic face off. Looks like it was like this for a while and the ribbon that goes to the front panel PCB fatigued off.I replaced the ribbon and Voila! It works!I contacted Keithley to get a replacement plastic front panel but they aren't coming to the party. (Last time I buy old Keithley gear!)The bits that are broken are the tabs that hold onto these pins on the side of the case to keep the face on.Can I repair these? I was thinking of glueing some plastic on but what sort of plastic?I did contemplate rebuilding them in epoxy/fibreglass and then sanding them down to size but this could become a mess.Any ideas?Tom

author: TiN
author_rank: Super Contributor
timestamp: October 22, 2014, 04:21:04 am
content: Those pesky ears easy to break.I'd suggest go with rebuilding with fibreglass, as that's the only way front panel mounts to chassis, and all force when you press buttons transferred to these ears.What is your location? I might have one of extra front panels, it's from 2001 tho. Layout is same, but button labels different.

author: tombi
author_rank: Regular Contributor
timestamp: October 22, 2014, 04:47:32 am
content: Thanks! I'll give that a go.I'm in Australia. I think I'll just patch it up and sell it. Very unimpressed with Keithley. Don't get me wrong the hardware looks great but the service!I don't understand why this is so hard for Keithley - the local distributor (Scientific Devices Australia) said it would cost *hundreds* of dollars for the replacement part! The Singapore service centre initially referred me to SDA but now aren't replying to my emails. I've emailed the info@keithley address but no response!One if its front feet is broken too but I found you can buy something called a 2000-BENCHKIT for about $30USD that includes the handle and all the feet.Tom

author: mij59
author_rank: Frequent Contributor
timestamp: October 22, 2014, 04:52:43 am
content: Hi,Make a M3 thread in the remaining of the ears and bolt it to the top cover.

author: SeanB
author_rank: Super Contributor
timestamp: October 22, 2014, 04:55:10 am
content: Those are easy to fix, just get some plastic of the same type ( most likely a polycarbonate of some sort) in a similar thickness and cut out matching ears, then use a soldering iron tip you do not like ( temperature at around 150C) to carefully melt the 2 plastic parts together. Trim afterwards to shape and add thin reinforcing strips to the inner side for extra support. You can do the same for the side places that have been bent. Often for the ears I use a cleaned and sanded paper clip to ad extra rigidity and support, melting it into the surface and using a filler piece to cover it over. Looks crappy unless you sand it down afterwards but as it is inside and stronger who cares.

author: BradC
author_rank: Super Contributor
timestamp: October 22, 2014, 02:21:02 pm
content: Devcon Plastic Weld.

author: tombi
author_rank: Regular Contributor
timestamp: October 22, 2014, 02:46:00 pm
content: Thanks!I found an old PC drive bay cover that looked to the the same sort of plastic and was the right thickness. I got as far as cutting the pieces and cutting off the broken bits so they are flush with the surrounding plastic but haven't tried attaching them. I cut the broken bits down as the plastic is thicker at the bottom and I thought it would bind better.Trying to decide if I drill the holes before I glue them or after - after seems more likely to be accurate.I'll check out the plastic weld!

author: robrenz
author_rank: Super Contributor
timestamp: October 22, 2014, 02:53:17 pm
content: If the plastic is ABS then MEK or Acetone will do a great solvent weld of the material. You must give several days for a full strength cure so be patient, don't try to assemble an hour later just because it feels solid.

author: BradC
author_rank: Super Contributor
timestamp: October 22, 2014, 10:44:58 pm
content: Used Bunnings gift cards (PVC) make great plastic for use with adhesives. The Devcon Plastic Weld is fabulous. So much so that I ordered a 100 blank PVC ID cards off E-bay and the interior of my car is held together with bits of PVC card and Plastic Weld (the factory 30 year old ABS is gradually breaking as the plasticiser leaches out with heat and UV). It's like JB Weld for plastic.

author: tombi
author_rank: Regular Contributor
timestamp: October 24, 2014, 01:12:17 am
content: Devcon plastic weld came in the post today. Will have a go with this tonight!As I wasn't getting any response from the local distributor, or the Singapore service centre I emailed Keithley. They came back with:"Now the part comes as a front panel assembly and the part number to order is RPT-FP2701. This part include front panel (2701-310-front panel, 2700-313A-overlay and 2701-311A-Display lens) You can order this through Scientific Devices. If I am not wrong the price is around USD200 you can confirm this with our distributor. Let me know if you need any more details."Then today the local distributor came back with"Our apologies for the delay. The parts just meet the minimum order requirement from that Keithley Department.This part include front panel (2701-310-front panel, 2700-313A-overlay and 2701-311A-Display lens), unfortunately they do not sell the individual parts. Also we cannot match the US Price list as we use the ASEAN (International) Price list.Model 2000-benchkit $49.00 + GSTModel RPT-FP2701 $396.00 + GSTFreight is $130.00 + GST/order."I thought $200 was bad enough but over $500 for essentially three bits of plastic is a bit over the top. And $130 shipping for something that probably weighs 200g max.I know it is a limited production item and the cost of keeping parts is probably quite high. I also realize this is an expensive bit of kit but nah... Sorry they don't want people repairing them.I think I will decline their offer.To think I used to complain about paying $50 for a replacement plastic skin for a domestic appliance (dishwasher etc).Tom

author: BradC
author_rank: Super Contributor
timestamp: October 25, 2014, 05:59:09 am
content: Quote from: tombi on October 24, 2014, 01:12:17 amIf you want the absolute best chance of having it work well, rough up the plastic to be bonded and make sure it's completely clean (I use acetone on a cotton bud for cleaning and a double cut carbide bur in a dremel for the rough up). The rougher the better and it can't be too clean.There are only two things I've not had success with. Teflon and HDPE. Teflon I just replaced, and HDPE I bought some HDPE welding rods and learned to plastic weld with my Aoyue 968 hot air gun (works a _treat_). Anything else seems to work with Devcon.

author: tombi
author_rank: Regular Contributor
timestamp: October 29, 2014, 01:34:10 pm
content: Thanks for all your help with this.I glued support pieces on when I stuck the drive bay pieces to the stubs but I realized later I don't have enough clearance for these and had to dremel them off.I drilled the holes after gluing them on and this worked pretty well. The bond is pretty firm. I drilled 1mm pilots before drilling 7mm holes (original was 6.5 I think but this seemed too tight).Attached are photos of the drive bay cover I used, the tabs sawn off, tabs drilled and assembled unit.I ordered the benchkit from Testpath to replace the front broken feet.Tom