Author Topic: WaveTek DM27 meter issue  (Read 422 times)

0 Members and 1 Guest are viewing this topic.

Offline Serracin

  • Newbie
  • Posts: 2
WaveTek DM27 meter issue
« on: October 16, 2018, 02:51:37 pm »
This meter is showing erratic measurements.
If I remember right, there is a chip that needs to be changed
Any ideas please?
 

Offline coromonadalix

  • Super Contributor
  • ***
  • Posts: 2062
  • Country: ca
Re: WaveTek DM27 meter issue
« Reply #1 on: October 16, 2018, 09:37:18 pm »
service manual :

https://elektrotanya.com/wavetek_dm-23xt_25xt_27xt_info_sch.pdf/download.html
or
http://www.xn--80alh0b.xn--p1ai/DOWNLOAD/dm27.pdf


The main chip is an icl 7106  and doesn't cost a fortune,  Datasheet : https://www.intersil.com/content/dam/Intersil/documents/icl7/icl7106-07-07s.pdf

You have a couple of TLO62  op amps,  and u70  is an 3ra024 ic, i think its an proprietary ic ???  seen old un-answered threads for searching this same ic ???
« Last Edit: October 16, 2018, 09:57:02 pm by coromonadalix »
 

Offline lowimpedance

  • Super Contributor
  • ***
  • Posts: 1062
  • Country: au
  • Watts in an ohm?
Re: WaveTek DM27 meter issue
« Reply #2 on: October 16, 2018, 11:26:29 pm »
This meter is showing erratic measurements.
If I remember right, there is a chip that needs to be changed
Any ideas please?
  Just a thought if its kind of functioning, perhaps a very good clean is a simple enough exercise. From the outer casing, input terminals to the PCB itself.
Check for any bad/cracked joints etc. and the switch selector traces are in good condition first before thoughts of chip replacement.
Contamination around the ADC of the 7106 will manifest as unstable drifting measurements.
Note, without pictures I have no idea how clean or otherwise your unit is!.
 If cleaning does not help then a good think as to whether this meter is worth further effort or its time to treat yourself to a new DMM. depending on how many you already own of course  :P.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf