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I just bought one on eBay I’ll see your other videos

Hi, i have a 310A, i would like to know if it is normal that whith auto trigger i am not able able to display properly the square wave from the calibrator. (With manual works fine) Thanks

I have a new one of it for sale

Hello, I have a 310A but it doesn't want to work, no trace, I changed all the electrolytic capacitors and the output voltages don't match those described in the maintenance manual.... can you give me any suggestions?

Schematically, Astron supplies are pretty good. BUT, the way that they are built includes sky-wiring, and marginal transformer designs. The PC boards are supported by the filter capacitor and working on them is a real pain. NONE of the primary supply connections have protective heat shrink on them either, so BE CAREFUL working on them. Consider them home brew supplies.

Great video! So was that bus a standard bus or did they use something proprietary?

What causes voltage drop when on load

Btw, the crowbar should blow the primary fuse. This is why it is critical to use rhe correct size and class of fuse. If the repeater had battery backup connected with the PSU, when the PSU goes off the battery voltage will feed back thru the pass transistors. You can install a diode in series with the output to prevent this..

Astron, Pyramid etc. These are all cheap PSUs and the Astron and Pyramid circuits are almost identical. Both using an LM723 with a driver transistor driving the pass transistors.

I have an RS-35A that’s not working. When I turn it on, there is no output voltage and the heat sink gets very hot after about 3 min upon switching on. What could be the issue? It’s an old model the transistors manufacture numbers are 8644. Unfortunately the serial numbers stickers were removed.

I'm working on a RS-35M the problem may be a result of the "in-rush current" just about every time I turn it on there is a (Bang! or Thud!) Sound. Now after using it very casually over the past 5 years mainly for monitoring and not so much for transmitting (meaning low current draw all those years) The unit will not turn on correctly anymore it "cycles" on/off sort of before it will stay on. This past week it finally stopped doing that and now it just endlessly cycles on/off, by this I mean the meters go low than up, then low than up, over and over again and it will not reach or stay where the meters should be. I assume that it's the "crow-bar" protection and will use some of your troubleshooting advice to locate the problem.

Fun! :-) Was that inspired by the famous COSMAC Elf "Enterprise" demo screen or a coincidence?

warning, warning, warp jump config error, stuck in loop ;)

me too thanks for sharing

I've seen one 12v zener diode rated at around 5000w a while ago

When I was employed as a Civil service worker for the Government, I repaired many of these signal generators.

Hi. I have a Astron RM-12A. It has a power switch on the front that kinda flickers. Any thoughts on what could cause this and if it will be an issue? Asking because I had the supply randomly turn off. I unplugged it and waited plugged it back in and it works again. Appreciate any insight you can give.

And Lee Hart is pretty flexible, often being willing to sell partial kits at even lower prices. So you could perhaps buy the Memberhip Card without that third 'front panel' circuit board, and perhaps also without the LEDs and toggle switches, and just build the rest of the kit as the core of a more traditional ELF computer for which you provide your own front panel, larger and easier to use toggle switches, different LEDs, etc;

Analog computers ?

Thanks.

The 723 has foldback current limiting, and the short circuit current on mine is just 1A when the crowbar trips.

Love to see the next video in this series. I have a 722-MD and didn't realize you subtract the dial. Thanks to your video I can used it now.

Take the ums and uhs out and this video would be 5 minutes shorter

Pure beauty....

I've got one of those and several other pieces of equipment in my building

More wisdom than repair info here, but very good advice. My FT-101ZD Mark I bought new is still my favorite rig after using many others. It seems that old radios don't like to sit for years and need to be used from time to time to keep them young.

A friend had a high voltage failure in the transformer. And contacted the factory. They stated that the transformers life had long exceeded its lifetime and was no longer available. And stated the scope had no warranty and was past it’s expected lifetime. Anyhow they sent a brochure for their current models of scopes.

Thank you very much Sir! A nice intro on this letter logic analyzer in real application.

Hi, do you recall where you found the manual online for this meter?

I remember the H.P., Hickok and Tektronix "monster series" test equipment very well. Had to pickup and deliver calibrated test equipment to the user. The equipment was rugged and surprisingly accurate after a long warmup. We had to perform mechanical adjustments when needed for the dials.

I found one of these in Spokane WA the other day and was wondering what it was used for? Thanks for explaining the knobs and dials

👀 👍

Id like to make a system with an 1802 myself sometime. do you by any chance know who the supplier or manufacturer of the chips are? Im not finding anything on mouser or digikey.

I used to own a 605B, but made by Federal, apparently under the license sharing of WWII. Mine worked but drifted badly. The remedy was to replace the triode oscillator tube with a 6C4 using a home made socket adapter. I also ran the set from a regulated B+ supply. The combination of these adaptations made the generator far more stable.

Hello, Nice work on the 310A! I own one too, fully functionnal and clean for the last 20 years, serial #17231, it's within a few hundreds units from yours, lol I use it for my high-voltage tube stuff, somehow I trust it more for HV than my other ones from the '80s :-)

I would just say I have repaired many of these, when the SCR clamps it's supposed to blow the primary fuse, Iv'e never seen one with the proper size fuse do any damage to the power supply, it's a good idea, I'd rather toast the power supply than a radio that cost a thousand dollars, I added the SCR to my personal supply on the bench, and the only problem after 20 years was a short in the rectifier, not bad, I hardly shut it off. for the money about the best linear supply you can buy.

I have a 608E that is just sitting here collecting dust. Is it of any value to anyone? I hate to just sit on it if someone could actually use it. Are they easy to get? I got mine from a local college that was retiring a bunch of gear.

Just stumbled over your video in a general YT search of oscilloscope. Those pcb through hole rivets on ancient pcb's was the first attempt of the wellknown VIA's or plated-through holes used nowadays. Back in the early 80's I used to work in a telephone company producing the earlier style turn-dialer telephones. The rivets used for VIA's they called "griplets" and were to be fitted as first pcb assembly operation on a special automatic riveter. This machine had a pretty fast X-Y table, so the constant distinct and loud clicking from the riveting operation was audible all over the factory. The phones did not suffer from the same connection problems as the Tek, as the pcb were wave soldered.

I have one to. Can you make more videos of this unit

A very good video! Thanks a lot. Lucky that I chanced upon this channel! keep up the good work. Love your enthusiasm and the methodical way in which you explained from the very beginning. Thanks again!

does this VNA measure group delay over frequency?

Looking at the pdf Manual I found on the internet (see WARNING) the BNC connector replaced the UHF after Ser. No 19119. However, mine is No 10764 and has a BNC, apparently as built. 310 Ser. nos start at 10000. WARNING - The file I downloaded from the internet - tektronix_310a_vintage_oscilloscope_sm (14824 kB) - worked fine as a computer file, displays correctly, but when I went to print it, corrupted my HP M277 printer, and jammed up the Printer Queue solid. After a couple of days, I got it working again with HP Dr Print and Scan. Tried other files, no problem. Tried the 310A manual again, same fault. At least I know the solution, now!

Thanks for sharing the video. I am purchasing a 101ZD MK2 in a few days.

Hopefully by now you have it going like gangbusters. I am still using my 101ZD that I bought new when they first came out back in the late 70's. I have bought new rigs since, but I always fall back on this rig. I have never put a screw driver to it. The receiver is great, but the reason I keep on using it is the Tube Finals. Can't beat a pair of 6146's.

My 35m astron will just ( audible click ) and drop voltage to 0. It does it when I have been using moderate amps on fm modes. It does it at 12 amps. Thats low current for a 27 amp continuous duty rating. The gauge lights stay lit, just no power out. I turn it off and its fine,,, Not sure whats going on. I can run it at 100 watts fm and draw 20 to 22 amps with no issues, just seems the extended use trips something. I can still lay hands on heat sink, hot but doable with bare skin. I know enough to know I don't know enough to fix it.

Thanks, I learned a lot.😀

Cool. Looks like my own workbench.

Loved this. I recently acquired a 200CD myself. Thanks to your tip I'm pre-emptively ordering replacements for those mica bypass caps!

I know this is an old thread, but i wanted to add a couple of comments about the rf section "tuning" that those who are not familiar with the the 608 series may find useful if they are restoring one of these units. As the author of this video points out, the oscillator and power amplifier are tuned together by a worm drive shaft which rotates a pair of multiplate air gap capactors . It's very possible that after so many years that the grease used to lubricate the bearings has dried up and for the rf amplifier tuning to "lag" behind as the frequency knob is dialed across any one band. This is undesirable as it will cause the output power to vary rapidly rather than gradually. This lag is caused by the shaft binding or dragging. If the design did not have the slipjoint that is part of the Amp Trimmer control, the two capacitors would remain in mechanical alignment and the increased drag would be felt by the operator as the frequency knob is turned. You can observe the slip joint as the frequency dial is turned, and the "lockiing pin" should stay at the same depth in the slotted housing. If the RF section has any binding, the pin will move forward or backward relative to the slot. You may observe the pin moving, and when the spring tension increases enough to overcome the friction of the bearing, it will often audibly snap back into place. The issue then becomes how to free up the rf amplifier tuning which is complicated because HP used a shielded bearing which is pressed into the top of the rf housing. Removal of the bearing is not a trivial exercise as it requires taking the lid off of the rf section and removing the variable capacitor - Guaranteed to be a nightmare both in disassembly, reassembly and then bringing the rf tuning back into alignment. I had this exact problem on my 608 and i spent a lot of time thinking about how to solve the issue. First i cleaned all the external rotating parts including the gears and non-sealed bearings with contact cleaner and a variety of rags and medical quality q-tips until all the old gease was removed - It took a while. Then it was time to deal with the sticking RF section tuning shaft. I did NOT want to flood the bearing with oil. The reason HP labeled the shaft bearings on the oscillator and power amplifier stages with "No Oil" warnings is that if oil passes through the bearing, it will drip down into the RF housing where it can foul the plates of the air capacitors. Since we're dealing with shielded bearings instead of sealed bearings, i chose to use a contact cleaner with silicone as my initial lubricant. I puddled the contract cleaner on top of the bearing and after it flowed inside, i then turned the whole unit on its side while rotating the frequency knob forward and backward across the whole band end-end. After a while the RF amplifier shaft was turning more freely, but it still would stick at several spots I then used 3 in 1 oil SPARINGLY but puddling small amounts on to of the bearing, and as it was absorbed, i rotated the unit on its side all the while turning the frequency knob throughout its range. Eventually, i did manage to achieve a fully tracking RF section - I hope my approach is sufficient to last long term. Update: It turned out i was only partially successful in trying to free up the bearing using the above method - it would still stick occasionally. So i tried this method: I removed the washer and snap ring, flooded the top of the bearing with some 3 in 1 oil, and applied heat from a heatgun. I was careful to keep the temps only moderately warm, warm enough to heat the bearing and the grease inside, and hot enough to thin the oil so that it would flow into the bearing. It took about ten minutes for the oil to penetrate and i had to do it twice. I know that this risks oil possibly flowing down the shaft and into the tuning capacitor, but i deemed it worth the gamble to avoid having to take apart the whole tuning mechanism.

Love to see old HP instruments, thanks for posting. The dials were all the same. To calibrate the frequency dial, there is a procedure. Basically, you set it to a certain frequency and if the dial is loosened in a specific manner so that the frequency does not move but the dial does, then you can rotate the dial to the correct frequency as determined by a counter. Lock the dial down at the measured frequency and it set. I think the front cover has to be removed. If you don't already have one, get the manual.