| The Shop > Electronics & IC Programing |
| Fluke 78 multimeter |
| (1/3) > >> |
| naffsharpe (Nathan):
Can anybody tell me where (uk) can find someone to repair the above or point me to a circuit layout? I need the Hertz function for a test but the meter seems dead. I've checked the obvious but no joy. Nathan. |
| John Swift:
Hi Nathan the user and maintenance manuals can be downloaded from Fluke http://www.fluke.com/Fluke/uken/Support/Manuals/default.htm?ProductId=56130 do you see any thing displayed ? - see service manual page 3-8 for display test my first test would be to try the low ohms / continuity range to see if it beeps with the input short circuited if it beeps some of the circuit is working , no beep could indicate a problem with the power supply circuit I've had old LCD displays fail when stored in over winter in the shed ! John |
| naffsharpe (Nathan):
John, many thanks for your reply. Component E1 as identified from the circuit diagram appears to be split/cracked. It looks like a capacitor outwardly but no capacitance is given on the diagram just 1500v/20% . I'll look for it online but any suggestions are always welcome ! Nathan. |
| naffsharpe (Nathan):
My apologies John, in answer to your question, I have no display at all, no continuity buzzer in fact absolutely zilch! This was an expensive meter when I bought it some time in the 1990s and would love to have it working as it was - like now when I need it ! It was in daily use and then it stopped working without any warning/ apparent damage . Last general use was with the thermocouple to see how effective our heating was (last winter) inside versus outside after much draught proofing/insulating/resealing of fire box and it worked faultlessly. Nathan. |
| John Swift:
Hi Nathan looking at the circuit diagram E1 is a spark gap (SURGE PROTECTOR,1500 V,+-20%) some I've seen looked like a disc ceramic capacitor with a saw cut forming the spark gap as it looks like dead - do you have continuity between the battery connections and each end of diode CR1 ? then , check you have power to the IC U1 battery +9V on pin 4 (via a diode CR2) and -9V on pin 40 (via transistor Q7 and switch S1) John |
| Navigation |
| Message Index |
| Next page |