Good point. I did nab the 3478a off him. The thing was shown passing self test so I figured the worst things that could go wrong are covered.
About six weeks ago when I was making an instructional video for a non-profit group I help out, I discovered that the 3478A "SELF TEST OK" message on powerup can be misleading about the current measurement path. I very rarely ever need to loop through a meter to take current measurements but in this case I needed to and discovered the protection fuse in the current jack was open and this isn't detected by the selftest sequence. I'd never needed to use that meter for current measurement before so I hadn't discovered the problem. I used the other 3478A on the bench instead and carried on with making the video.
Anyhow, this is something that needs to be checked manually on the 3478A as it turns out.
I got some replacement fuses a few days ago. Maybe later this afternoon I'll venture down into the basement and put a replacement in and see if it's just the fuse or if there's more extensive damage to the meter hiding behind the everything's ok message.
Very true. I’m going to do a full checkout on this. I suspect it’s probably ok with the riskiest things being the back being munted, the fuses popped, the current range smoked or the front/back switch being dicky. Time will tell!
Going to replace the cal battery as well. This time I’m going to assume I’m going to fuck up and actually back the cal data up over GPIB first.
Good point. I did nab the 3478a off him. The thing was shown passing self test so I figured the worst things that could go wrong are covered.
About six weeks ago when I was making an instructional video for a non-profit group I help out, I discovered that the 3478A "SELF TEST OK" message on powerup can be misleading about the current measurement path. I very rarely ever need to loop through a meter to take current measurements but in this case I needed to and discovered the protection fuse in the current jack was open and this isn't detected by the selftest sequence. I'd never needed to use that meter for current measurement before so I hadn't discovered the problem. I used the other 3478A on the bench instead and carried on with making the video.
Anyhow, this is something that needs to be checked manually on the 3478A as it turns out.
I got some replacement fuses a few days ago. Maybe later this afternoon I'll venture down into the basement and put a replacement in and see if it's just the fuse or if there's more extensive damage to the meter hiding behind the everything's ok message.
I got one that passes self test but won't read anything on the AC ranges, DC works fine.
I think 99% it's the hybrid module, so when I get it back from my brother, I'tt swap the known good module from my second unit to test.
I'm hoping it is actually something simple like the relays, but I'm not holding my breath.
Fingers crossed its something simple. It’s easy to blow up the AC ranges on them.
Anyone want a dead 1502 TDR for 69 quid? https://www.ebay.co.uk/itm/254668339698
That seller had a different one for £95, in June. I made him an offer (below £69) and suggested photos of the rear, but he declined.
There are too many things that could be badly wrong with it; it isn't worth £69 to me.
Good point. I did nab the 3478a off him. The thing was shown passing self test so I figured the worst things that could go wrong are covered.
To note if something is munted and not pictured, it's an instant paypal refund so it's low risk.
Even if it is "parts or not working"?
Looking closely, there seems to be a white deposit on the recorder knurled knob, the case top lip, and the screen. If the case is intact and if it had the x-y plugin rather than the chart recorder, then I wouldn't worry too much about the sealed interior. Plus the simplest way of cleaning it would be to put it in a dishwasher. (Not in a clothes washer, since the drum would be damaged).
As it is I've got an excellent spare 1502 I want to shift, so it isn't tempting at that price.
Yeah if it’s worse than you expect then parts or not working doesn’t count.
Edit: to clarify this point, if you buy something on ebay and it arrives other than as pictured or with damage that wasn't depicted or does not perform the same test steps illustrated in the auction or the photographs were taken disingenuously to hide damage then ebay refund the buyer unconditionally.
Don’t however open it or you’ll lose instantly.