QRP Labs
Frequency counter PDF Print E-mail
Written by Hans Summers   
Saturday, 11 July 2009 09:06

Frequency counter data from Rick Peterson 2E0JSI/M3JSI:

Rick did some very nice work on the LCD frequency counter / clock module of the radio. He worked out all the pin connections and how to put the display in 1kHz resolution mode. He has built a homebrew 80m Superhet receiver with 455kHz IF, and fed the receivers VFO directly into the counter, which successfully displayed the frequency first time.

Click the photograph (above) to see Rick's homebrew 80m Superhet in more detail.
CLICK HERE to read Rick's analysis of the frequency counter
Later he pointed out that the frequency counter IC is "upside down", i.e. LCD connections are at the top, not the bottom.
CLICK HERE for a couple of further notes from Rick.

More frequency counter data from Chris Williams G7NBP:

Chris confirms Rick's information and makes one minor correction to the ribbon cable connections.
CLICK HERE to read his email to the GQRP list.
Since writing that email, Chris has investigated further and determined that the IC is labelled KFD SC3610 0504 HP. This is the SC3610 IC which from the datasheet, appears to be identical to the UTC6610. Chris' picture is shown above.
Chris' advice on removing the LCD:
1. Be very careful of static electricity: he destroyed his IC like this :-(
2. Unsolder the plate screen from the PCB and remove
3. LCD is held on by double sided sticky pad - the LCD can be very very very gently pried off, but a safer approach would be to lift a corner and dribble a squirt of label remover of perhaps WD40 under it to weaken the adhesive.
4. That's it: Conductive ribbon cable is bonded at both ends, so it is safe to life the LCD and run at 90 degrees to mainboard if space is tight.

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