Recently acquired more video equipment and thought I would post about it here, no doubt many of the ex-trade among us will have come across the same or similar, in their time.
Although not much use on my current Philips N1500 repair this might come in handy when I get around to the various VHS players.
What we have here for those unfamiliar is a test meter used for determining whether a video head is in good condition by detecting the wear/state of the head and indicating its state on the meter. The YF-225V was for VHS heads and the YF-225B for Betamax.
There are three ranges to select and each range has a calibrate setting. Before testing one needs to determine the video head under test and select the appropriate range.
- Range A approx 0.2 - 3.5uH (inductance point of 0=0.9uH)
- Range B approx 0.8 - 3.0uH (inductance point of 0=1.4uH)
- Range C approx 0.5 - 1.5uH (inductance point of 0=0.85uH)
I did a quick test of a NOS head, I had no idea what range to select so tried them all.
Range A gave a reading on the meter (shown below) of 6, Range B gave a reading of 5.5 and range C gave an off-scale reading as though the meter was in the off position. When time permits I will have a deeper delve into the workings and scan the manual for the data library.
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I have had one of these for VHS heads for about 25+ years and have never used it.
Jon
BVWS Member
I was only fixing VCR’s for about 3 years, these were not available, or if they were I didn’t know about them.
I seem to remember using a scope either on the output of the heads or the head amplifier. I possibly just recognised what picture a faulty head produced, whichever it’s long forgotten.
Frank
I remember when these (or similar) first came out, they were advertised all over, certain reps also tried to push them on to us.
I personally always thought they were a bit of a gimmick, having said that I never bought one or used one so cannot really objectively say if they were any good or not.
Like Frank said above we just used a scope on the FM output test point.
Ps. I will still be interested to see how you get on with it.
Hi.
We had one in Clydesdale and I certainly never used it and I have to say didn't see any of my colleagues use it either. Like any job in the world you gradually get to know symptoms that you see and hear and can make a pretty good diagnoses by experience. Looking at the signal from the head amp though is as accurate as you'll ever need.
I'd say the tester is handy for a really knackered video to check the heads to see if they are worth salvaging, so it certainly wont go to waste.
Cheers,
Trevor.
MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member
Yep, we had one too. Remained unused in it's box!
