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No V-sync

See Report by Bernd (German)

Symptom: Screen V-sync was very unstable, adjustment range insufficient.
Root cause: C521 (1 μF) in phase detector circuit was found installed with incorrect polarity, presumably ex factory (original-looking solder joint). High leakage current resulted.
Fix: Replace C521 (install with correct polarity).



  • The 1240/1241 will tend to accumulate dust because of the large quantities of air flow needed to ventilate the device. The front screen uses a combination of LEDs and phototranstistors to sense presses. Dust and other particles can accumulate on these components leading to failure.


Backup battery


(Pic1) Controller processor board

The 1240 and 1241 retain configurations in battery-backed RAM. In most instruments, the battery is a Catalyst Research 3440LP. Over time, this battery will deplete and unltimately leak. A leaking battery can destroy components, PCB traces and metal.


The old battery can be de-soldered and wires can be soldered in to connect a new battery. It is up to the user to decide what type of battery they will use, as long as the battery voltage is about 2.9 V. The new battery can be placed wherever appropriate.


(Pic2) Wires on the board
(Pic3) Battery has been placed behind the fan

So far I've had no problem with this fix I've had the battery installed for over a year. I used a CR2032 battery, but it's not the best solution because the analyzer will try to recharge it.

--Floopy (talk) 05:09, 4 May 2019 (MST)