Repaired/No Longer Need: HP 606A T212 - Page 1
Forum section: electronics / general

author: W3SLK
author_rank: Contributor
timestamp: February 03, 2024, 11:00:29 pm
content: I'm looking for a T212 (or T206), for my sick 606A signal generator. If I could find the coil or a turret with it on I would be happy. Please let me know your price.Thanks,Mike(y)/W3SLK

author: Stray Electron
author_rank: Super Contributor
timestamp: February 04, 2024, 12:42:53 am
content: I'm going to a very large hamfest in Florida next weekend. Post your location and the level of pain that you can handle and I'll see what I can find. Do you know if any other models use the same x-former?

author: W3SLK
author_rank: Contributor
timestamp: February 04, 2024, 04:35:00 pm
content: Stray Electron said:QuoteI would like to get anything under $30 if I can do it. I have seen these sig. gens show up for less than that. T212 is the same as T206 on the RF Osc. turret. I hate like the devil to ruin a unit just for 1 part. I would like to make it to that hamfest one of these days if it is the one I'm thinking of. All the big ones around here, (Timonium and Gaithersburg) have met their demise!Mike(y)/W3SLK

author: Stray Electron
author_rank: Super Contributor
timestamp: February 05, 2024, 02:11:23 am
content: If you want to go to any hamfest then you'd better do it soon. They're ALL dying due to competition from E-ham and Fleabay.Don't worry, I won't scrap a good unit for just one x-former. If I find anything for that price, it will be one step away from scrap metal anyway.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 05, 2024, 02:23:54 am
content: Quote from: W3SLK on February 03, 2024, 11:00:29 pmI had a look at the 606A service manual and I don't think that anyone can remove a T 206 or 212 without affecting it's value. I think it's going to be necessary to remove the entire turret plate with all of the coils and resisters. But I'm surprised that either of those coils are bad. Are you sure that the problem isn't a bad contact in the switch or a bad resistor?Page 4-16 herehttp://hparchive.com/Manuals/HP-606A-Manual.pdf

author: factory
author_rank: Super Contributor
timestamp: February 05, 2024, 07:26:33 pm
content: Well that explains the "not separately replaceable" comment, for all of the turret transformers in the 606B.The tuning slug didn't survive, see the thread on HPAK groups.io;https://groups.io/g/HP-Agilent-Keysight-equipment/topic/hp_606a/103998583Also the 606A book lists different part numbers, for the primary coils of those two transformers.David

author: Stray Electron
author_rank: Super Contributor
timestamp: February 05, 2024, 08:09:36 pm
content: I didn't take a deep dive into the various HP 606 manuals but it's also possible that different batches of the HP 606A use different coils/capacitors/resistor combinations. But I will keep my eyes open and see if I can find anything.

author: W3SLK
author_rank: Contributor
timestamp: February 06, 2024, 09:38:31 pm
content: Yeah the NSN 'scalpers' want a kings ransome for it but shows they are available. I installed a slug but I get more output from it when the slug is totally removed. I don't know if there is a problem with T212 or not but as David said, I destroyed the ferrite slug, (polyferrite is how it is described). Maybe I ought to post in the Troubleshooting forum. But I think most who are here are on io.groups/HP also. Also I think I was scammed by someone trying to sell one on here. I may be saved by American Express though!

author: W3SLK
author_rank: Contributor
timestamp: February 09, 2024, 03:53:18 pm
content: I posted this on the HP io.groups forum incase anyone looks. Just to give an update. I think I found the culprit to my issues on band 6. I was on target when I suspected the RF amp coil. Anyone cares to correct me on my assumptions here please do but I think I am on or close to how things work. I will attempt to post a photo. What I noticed is in the RF osc., when cycling the tuning capacitor from one end of the band to the other, (regardless of band), the output will breathe, or go up in amplitude and down. I think some of it has to do with a proximity effect as the tuning cap passes the mounting screws, (it also may be coincidental that it happens at that point). The RF amp, along with the differential amp try to maintain a constant output by adjusting its output 'automatically' and resulting in a nice pure output. What I found when I removed the secondary of the transformer for Band 6, is that the windings were shorted together. You can see where the enamel melted on the wires. This band was abused. The output was consequently attenuated and the differential amp in its effort to maintain output, would run as hard as it could but didn't have enough to maintain a constant output, especially when drive was increased. All I can say is that it was an engineering effort to create an instrument such as this and really appreciate all that went into making it!