TEK468 Problems - UK Vintage Radio Repair and Restoration Discussion Forum

Sci_Curios · 21st Jan 2014, 11:19 am

Hi folks,
I am looking for help with a couple of Tek468 scopes please.

I have one at a friends house in Gainsborough Lincolnshire and another here with me in Liverpool. Neither of us want to ship these pieces of kit back and forth, so if anyone can help us I would appreciate it.

Thanks
Jim

maninashed · 21st Jan 2014, 1:37 pm

Hi Jim, what condition are the 468's in?, are they functional? Not sure if you are aware, but the 468 is one of the most complex Tek scopes ever made, compounded by an early digital storage pcb, and a seperate power supply for the digital functions. Repair on one of these can soon get very costly and time consuming indeed. Don't want to dissuade you, but simply pointing this out.
Bill

Sci_Curios · 21st Jan 2014, 5:39 pm

Hi Bill,

I have 4 of the TEK468's. 2 with the GPIB interface and 2 without. They have been in long term storage for many years and are very dirty, and some switches I guess need a thorough clean but otherwise seemed in reasonable condition. They all power up and their self-test's go through with no errors. I just finished cleaning one up last week and sent it off to a friend in Lincolnshire. They have reported that there is a potential fault when it arrived that I don't think was there when it left Liverpool. Specifically, although the scope powers up the power on LED doesn't come on. Also in non-store mode the Auto sweep button does not seem to function. They just get a non-moving dot, but if they apply the calibrator signal then that dot becomes a vertical line. Before it went I tested the unit using auto sweep and it was fine. I am sure it is probably a connector shook loose but they are not experts and I don't particularly want to have to ship it back here to look at. The power on LED was also working when it left here. Could just shipping the scope cause these parts to fail or is it likely to be a loose connector?

Any advice you could give would be appreciated

regards

jim

Oldtestgear · 21st Jan 2014, 6:00 pm

I have fixed three of these before & agree that these early DSOs are incredibly difficult to work on as the PCBs are folded together into the case. If the ADC or memory has failed then the scope is almost certainly beyond economic repair as these parts are pure unobtainium. Some of the logic is also unavailable except on the grey market.

These scopes are definitely sensitive to damage in transit as some of the connectors can come apart which causes some strange faults. As I live in Torquay I am not in a position to help unless you can send them by courier. As a purely commercial exercise I would suggest that you will be lucky to get these repaired for less than £100ea. For a serious fault the price would be higher.

Hate to be negative but you might be better off cutting your loses unless you can find a sympathetic engineer willing to look at these for interest rather than for a living. I agree that these are nice scopes (I still have one under my bench in) but the technology is now pretty ancient.

Phil

maninashed · 21st Jan 2014, 9:03 pm

Hi Jim, as Phil (oldtestgear) has confirmed, these really are a complex, temperamental scope. From your description of the one in Leicester, firstly, if my memory serves me right, its not an LED, its a wire ended bulb, and it could just have expired in transit due to a knock etc. Secondly the display, it sounds to me as if the timebase is not running, check that its not stuck in X-Y mode. When in transit, the front panel knobs may have been pushed in by the packaging. Things like this can occur when some inexperienced person starts using an instrument such as these. If you can, get them to send you a good clear pic of the front panel controls, and then post it on here. Someone may spot the problem. Hope this helps.
Bill

Sci_Curios · 22nd Jan 2014, 12:41 am

Thanks Phil and Bill I will see what we can get as an image

regards

Jim

Sci_Curios · 26th Jan 2014, 3:51 am

here you go folks. Here are photos of the front panel whilst the fault is present. If anyone has any ideas on possible faults and their remedies please share

regards

jim

Sci_Curios · 26th Jan 2014, 10:27 am

oops looks like the pics did not attach first time. I will try that again.

maninashed · 26th Jan 2014, 10:32 am

You will need higher resolution pictures Jim, those are too small. Set the camera to a higher pixel setting.

21st Jan 2014, 11:19 am	#1
Sci_Curios Retired Dormant Member Join Date: Apr 2013 Location: Liverpool Posts: 9	TEK468 Problems Hi folks, I am looking for help with a couple of Tek468 scopes please. I have one at a friends house in Gainsborough Lincolnshire and another here with me in Liverpool. Neither of us want to ship these pieces of kit back and forth, so if anyone can help us I would appreciate it. Thanks Jim Last edited by AC/HL; 23rd Jan 2014 at 12:02 pm. Reason: Moved to Vintage Testgear section

21st Jan 2014, 1:37 pm	#2
maninashed Rest in Peace Join Date: May 2011 Location: Preston, Lancashire UK Posts: 955	Re: TEK468 servicing needed Hi Jim, what condition are the 468's in?, are they functional? Not sure if you are aware, but the 468 is one of the most complex Tek scopes ever made, compounded by an early digital storage pcb, and a seperate power supply for the digital functions. Repair on one of these can soon get very costly and time consuming indeed. Don't want to dissuade you, but simply pointing this out. Bill

21st Jan 2014, 5:39 pm	#3
Sci_Curios Retired Dormant Member Join Date: Apr 2013 Location: Liverpool Posts: 9	Re: TEK468 servicing needed Hi Bill, I have 4 of the TEK468's. 2 with the GPIB interface and 2 without. They have been in long term storage for many years and are very dirty, and some switches I guess need a thorough clean but otherwise seemed in reasonable condition. They all power up and their self-test's go through with no errors. I just finished cleaning one up last week and sent it off to a friend in Lincolnshire. They have reported that there is a potential fault when it arrived that I don't think was there when it left Liverpool. Specifically, although the scope powers up the power on LED doesn't come on. Also in non-store mode the Auto sweep button does not seem to function. They just get a non-moving dot, but if they apply the calibrator signal then that dot becomes a vertical line. Before it went I tested the unit using auto sweep and it was fine. I am sure it is probably a connector shook loose but they are not experts and I don't particularly want to have to ship it back here to look at. The power on LED was also working when it left here. Could just shipping the scope cause these parts to fail or is it likely to be a loose connector? Any advice you could give would be appreciated regards jim

21st Jan 2014, 6:00 pm	#4
Oldtestgear Hexode Join Date: May 2008 Location: Devon, UK. Posts: 307	Re: TEK468 servicing needed I have fixed three of these before & agree that these early DSOs are incredibly difficult to work on as the PCBs are folded together into the case. If the ADC or memory has failed then the scope is almost certainly beyond economic repair as these parts are pure unobtainium. Some of the logic is also unavailable except on the grey market. These scopes are definitely sensitive to damage in transit as some of the connectors can come apart which causes some strange faults. As I live in Torquay I am not in a position to help unless you can send them by courier. As a purely commercial exercise I would suggest that you will be lucky to get these repaired for less than £100ea. For a serious fault the price would be higher. Hate to be negative but you might be better off cutting your loses unless you can find a sympathetic engineer willing to look at these for interest rather than for a living. I agree that these are nice scopes (I still have one under my bench in) but the technology is now pretty ancient. Phil

21st Jan 2014, 9:03 pm	#5
maninashed Rest in Peace Join Date: May 2011 Location: Preston, Lancashire UK Posts: 955	Re: TEK468 servicing needed Hi Jim, as Phil (oldtestgear) has confirmed, these really are a complex, temperamental scope. From your description of the one in Leicester, firstly, if my memory serves me right, its not an LED, its a wire ended bulb, and it could just have expired in transit due to a knock etc. Secondly the display, it sounds to me as if the timebase is not running, check that its not stuck in X-Y mode. When in transit, the front panel knobs may have been pushed in by the packaging. Things like this can occur when some inexperienced person starts using an instrument such as these. If you can, get them to send you a good clear pic of the front panel controls, and then post it on here. Someone may spot the problem. Hope this helps. Bill

22nd Jan 2014, 12:41 am	#6
Sci_Curios Retired Dormant Member Join Date: Apr 2013 Location: Liverpool Posts: 9	Re: TEK468 servicing needed Thanks Phil and Bill I will see what we can get as an image regards Jim

26th Jan 2014, 3:51 am	#7
Sci_Curios Retired Dormant Member Join Date: Apr 2013 Location: Liverpool Posts: 9	Re: TEK468 Problems here you go folks. Here are photos of the front panel whilst the fault is present. If anyone has any ideas on possible faults and their remedies please share regards jim Attached Thumbnails

26th Jan 2014, 10:27 am	#8
Sci_Curios Retired Dormant Member Join Date: Apr 2013 Location: Liverpool Posts: 9	Re: TEK468 Problems oops looks like the pics did not attach first time. I will try that again. Attached Thumbnails

26th Jan 2014, 10:32 am	#9
maninashed Rest in Peace Join Date: May 2011 Location: Preston, Lancashire UK Posts: 955	Re: TEK468 Problems You will need higher resolution pictures Jim, those are too small. Set the camera to a higher pixel setting.