[labnetwork] TemEbeam beam coil issue

[Khanna, Rohit]

Hi Alexey,
                 I came across your mail regarding the E-beam evaporator we have a Edwards Edwards A500 FL500 thermal evaporator. Few years back we had a similar problem with the controller. I had to trouble shoot the unit. I would describe the repair to you, First you need to measure the inductance of the deflection coil in the chamber. There should be two set of coils for beam deflection in say X & Y direction these coil should have some reasonable inductance say around 10 Ohms. Please note the DC resistance if a false indicator and don't use a DMM to measure the resistance.

Once you are certain the deflection coils are not shorted out then try investigating the coil deflection unit. In principle this unit is essentially a two channel audio amplifier which is being driven by a two channel. In our case the final stage of the coil deflection amplifier was made up of an audio amplifier which had shorted out, in this case there is going to a constant DC signal being applied to the coil. I had to replace this amplifier and the part number for our design is LM3886T, in addition we also had to replace some freewheeling diode and the part number for that was RS3M-13-F or something equivalent. In case you are in doubt open the unit and share few pictures of the PCB.


Warm Regards
Rohit Khanna
Electronic Test & Measurement Engineer
London Centre for NANO Technology, UCL
Ph:+44-020-76799984
Lab: +44 20 3108 1516
Int Ext: 39984

________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Alexey Kovalev <kovalev at magnet.fsu.edu>
Sent: 20 September 2023 18:59
To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: [labnetwork] TemEbeam beam coil issue

⚠ Caution: External sender


Hello All,
We have an issue with the coil current for the e-beam evaporator and wondering if somebody had a similar problem in the past. We suspect that it is  related to the controller.

We have noticed an issue with the lateral beam sweep coil current in the Temescal TemEbeam controller (EBC). When the controller is turned on, the lateral beam sweep starts out at a high current of ~3-4 amps and is unable to be lowered using the lateral/latitude sweep position controls. This high current appears in the negative (left) region of the sweep pattern display area. We have checked the leads from the sweep coils up to the end of the connector attached to the “Sweeper Coils” terminal at the back of the controller, and no issues were found. We have also tried a full factory reset of the controller as well as unplugging/plugging in the power cable at the back, but the high current issue still remains.

Any advise would be greatly appreciated.
Sincerely,
Alexey

--
Alexey Kovalev
Assistant in Research
A302
NHMFL FSU
1800 E. Paul Dirac Dr.
Tallahassee , FL 32310-3706
kovalev at magnet.fsu.edu
TEL:850-644-0861
FAX:850-644-5038

5161 706C 6127

_______________________________________________
labnetwork mailing list
labnetwork at mtl.mit.edu
https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmtl.mit.edu%2Fmailman%2Flistinfo.cgi%2Flabnetwork&data=05%7C01%7Cr.khanna%40ucl.ac.uk%7Cb41cef9f4168460f16a908dbba052220%7C1faf88fea9984c5b93c9210a11d9a5c2%7C0%7C0%7C638308303443417412%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=QEYtvcIY52So%2FVZBqKZcTQjbGGll8E2p8ujge0ENsCk%3D&reserved=0<https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20230922/83b99812/attachment.html>