I love these little supplies! I have one that is this same exact model, and two more that are the 12V models. They are the main supplies I use on my bench everyday. Neon bulbs do have a limited life, so it's probably the bulb going bad. Either replace it with another, or switch over to an LED using the preregulated DC source in the supply.
+w2aew Yep, that's exactly what happened, bulb went bad. I replaced it with an LED powered off the -6.3V rail, works a treat. The LED even fits nicely inside the plastic sheath that the neon bulb used to be in, so it looks quite nice (on the outside anyway :).
+Minecraftism Haha, happy to oblige. It's super-hacky, but for a one-off, it works! ;) I was hoping for there to be more involved in repairing the electronics of the unit since it was sold as not working, but aside from the flickering neon lamp, there wasn't anything to fix! The flickering neon lamp issue is actually a good example for the subject of resistor aging, which will be covered in a later video.
+devttys0 You should think of a way to attach the meter by screwing it in. Glue some plastic tabs onto the meter and some mounts on the back of the enclosure face.
Sometimes the easy fixes make up for the tough ones. Duct tape is obviously an option but was wondering if the adhesive side is in any way conductive? (I'll have to jump over to the bench and check that!) The length you used appeared to cover the rear of the pots in the upper right quadrant and I couldn't see if they had exposed terminals or not; if they're enclosed then it's a non-issue. Hey, for $5 what a steal! 73 - Dino KL0S
+Dino Papas The duct tape does cover the terminals of the pots, but the kind I used is not conductive. Apparently "real" duct tape is made from aluminum foil, and would obviously be quite conductive! (arstechnica.co.uk/civis/viewtopic.php?f=11&t=772653)
I think fixing the intermittent power light issue is worthwhile. The manual shows that it's a neon lamp connected to the mains input with a series 47kohm resistor. (Talk about a design from another era) But there's +6.2V on the board. It should be fairly easy to replace it with an LED, possibly even re-using the original lamp holder on the front panel (and some hot glue). Great score by the way, and a very useful addition to the bench. exodus.poly.edu/~kurt/manuals/manuals/HP%20Agilent/HP%206216A%20Operation%20&%20Service.pdf
+dwDragon88 Yes, the series resistor probably needs to be replaced. The neon lamp seems to be held just at its firing voltage, and the neon itself is light sensitive, so I can actually control the flickering with ambient light. Shine a light on the neon lamp, flicker goes away; shade the neon lamp, and the flicker comes back. It's actually rather entertaining. :)
I just obtained one of these. 6215A but no light, no meter or voltage. any idea where to start looking ? Could it be the caps ? Thanks in advance for any suggestions... Michael87r
Will you be doing the on/off light repair as a video? I came across an older power supply that needs a new on/off switch (lighted) and need information on how to do it.
