Favorite meter unhappiness

[beamcurrent]

My Trusted Philips PM2618X, that has been my friend for 1/4 of a century is unwell.

Its reading high on DC, AC & ohms, or to be more accurate only high at certain voltages eg. measuring 1.5v gives a reading of 4.8V but 10 or higher (10-30) volts reads correct and as you reduce the voltage it remains at 10 for a bit then drops suddenly. AC also unpredictably high as are ohms.

All these readings are steady, no intermittent connections. inside the rather busy PCB looks like new.

it has new good batteries and the on board coin cell is at 3.4v.  

Has anyone got a circuit? or words of comfort? It has the feel of a stuck bit(s) in the A to D.

Brian

Hmm seem to have it twice?

[Mark Hennessy]

I have a PM2517, which is not exactly the same, but similar perhaps? I've just uploaded the service manual to The Archive: http://golbornevintageradio.co.uk/forum/...p?tid=5391

Have you manually gone through the ranges to see if it's a problem with the dividers rather than the ADC?

[beamcurrent]

Thanks for the pointer to the 2517 circuit, it is not quite the same, the 2617 has an LCD display and the power switching is different.

However I shall have a read and see if there is any help.

don't think it is the range switching, which is automatic, as the error appears in the same decade. I will need to get the valve PSU out for some higher voltages.

Brian