Horstmann E7 Quartz timer - Advice sought please

[Caterpillar53]

Hi. Thanks in advance to anyone who can help. A friend has a Horstmann E7 Quartz timer which is not working properly:
- The timer light does not come on at all, even if you manually spin the clock dial
- The boost light comes on but only weakly
- The clock will sometimes tck round for a while but then stops.
I suspect the backup battery and am capable of wiring in a new one but can't find any definitive info on previous posts about exactly what the spec of this should be. The battery that's installed is putting out 1.2V
Please can anyone supply info about battery spec, or have any other suggestions if you think I might be barking up the wrong tree by suspecting the battery?
Thanks in anticipation.

 

[CBW]

If you’re capable, check for a loose/dirty connection would be my 1st port of call.

 

[JohnD]

Post a photo of the batt. I think it will be green. Note the numbers on it. It might be a Varta Mempac. Some clock maintenance batteries are not rechargeable (there is no point in them doing anything else when power is off).

Test the mains voltage on the supply and on the load terminals, with the heater off, and again with it on. Do this before you tighten the screws. Then do it again after. What are the four figures?

 

[JohnD]

Here's one I did earlier

Onboard memory battery

I have a timer/programmer with an onboard battery to maintain the memory if mains power is lost. The manufacturers obviously didn't intend the product to last longer than the battery as it is soldered in place. It has the appearance of three button cells soldered together with pigtails and...

www.diynot.com

Yours is probably different, but if you post some pics we might know.