Products > Test Equipment
Protek 608: Fried by a "69"
k1mgy:
Is the reference generator synonymous with the ADC internal analog reference? This ADC Vref is 2.5V according to my testing.
Unless there is another reference I should look for beyond the ADC?
retiredcaps:
--- Quote from: k1mgy on December 31, 2014, 02:33:05 pm ---Looks like Protek is out of business, which is unfortunate as this meter is a mid-range cost, high quality unit with a good set of specs and features.
--- End quote ---
From this thread
http://www.antiqueradios.com/forums/viewtopic.php?f=8&t=58409
Hung Chang made Protek. Hung Chang is renamed to GS Instrument. The 608 is listed on their product webpage.
http://www.gsinstrument.com/02_product/sub01_01.php?board=board01&classcode=B01-4
Billy03:
The Protek 608 was sold rebranded as Voltcraft VC608 in Europe.
You can still download the schematic on the vendor's website:
http://www.produktinfo.conrad.com/datenblaetter/100000-124999/120277-sp-01-en-Digitalmultimeter_VC_608.pdf
I've fried my 608 too... and had to make heavy use of the schematic. ;D
lowimpedance:
Hah does look like a 2.5V ref diode. But what an awful schematic !.
philtulju:
Sad! I hope you all were able to do something.
Unfortunately the internet is way worse now in 2023 vs. 2014 or 2017 when this thread was active and the schematic link was live.
I did the same boneheaded thing and smoked my Protek 608 that is my favorite meter and that has served me well for more than 20 years.
Fortunately, I was able to fix it - in my case only one component, Q1, popped. Looking at the board Q15 and Q16 appeared to be the same component - SOT-23 marked big capital "N" then "OM" capital but smaller (or possibly "0M") and a date code sideways of "QB" capital.
Looking up the code was fruitless (got some hits for other components like the ZC that seem plausible; Korea Electronics 2N3904S NPN.)
Anyhow I took off Q15 and when measuring it noticed that it was behaving like an N-channel MOSFET. So I replaced my Q1 with a BSS138 that I had in my stockpile and my meter is back from the dead! YAY!
Now I've put a label on all my meters to help remind me:
[!] CAUTION [!]
self-measuring battery
can damage meter
Navigation
[0] Message Index
[*] Previous page
Go to full version