Does the Astron have a safety mechanism where if the pass transistors go short and the output voltage rises, they crowbar the output to ground to blow the fuse and protect your radio...

@@cthoadmin7458 Yes, there is a SCR used for over voltage protection. If the SCR fires it shorts the output to ground which should blow the AC fuse.

That's what I said when I saw one of these demonstrated for the first time. It has 48 bytes of RAM but only 47.5 bytes are usable, the last four bits are tied to ground and not used at all. Once you get past the learning curve it's a fun instrument to use. The ability to slow down, pause, or single step through commands really makes this instrument helpful. Thanks for watching!

I bought this radio new back in 2003. It's been my mobile work horse for many years, I only had to send it back to Icom only once to repair an issue with the unit powering on/off. I certainly would like to see Icom bring this radio back. Thanks for watching!

@CraigPetersen12f36b I found one with high serial numbers so one of the last ones manufactured for $500 in good shape

Hello Peter, by noise, if you mean phase noise I have not. Most of the reference outputs are square wave. However, the 5370B does have a sinusoid present on the reference out. Unfortunately, there are visible second harmonic products in the waveform and would do poorly in a phase noise plot. Like the 5370B, most of the gear I have are equipped with HP 10811A references, the others have the HP 10544A/B references. Thanks for watching!

@@CraigPetersen12f36b Thanks for the response. I was more referring to a noise floor test. This is where you feed in a relatively stable signal on the start channel and split via a longer known length coax to the stop channel, the time interval in theory should indicate the length of the cable but more importantly should be stable (There are a few better described refences available on the net) When I perform this test I am seeing fluctuations, In fact when I perform the basic confidence test in section 4 step 13 of the service manual I am seeing fluctuations from 99.65ns -> 99.71ns ie: several 100ps variation, The manual says the reading should be 100~1ns but does not mention if it should be stable, I would expect the reading to be stable but could be wrong, do you see such variations when performing this test ?

I just tried this test, my counter is fluctuating between 100.16 to 100.20ns, well within the +/-1ns. I can get it even closer to 100nS if I manually adjust the trigger levels on the front panel. I would expect this due to the velocity factor of the coax and +/- any counting errors. My guess the counter you have is operating correctly. I also used a HP 5359A Time Synthesizer and got virtually the same results. I have not tried this with two different lengths of coax going to the start and stop inputs. I may have to try that.

@@CraigPetersen12f36b Thanks for checking this out. Seems you are getting similar results to what I am getting. I have checked a few of my sources out but can't seem to get better that 1E-10 at 1sec Tau. Even my rubidium source measures 1E-10. it should be better than 3E -11. Al other Tau are within spec though. Maybe I am expecting too much from this unit. I noticed in your quick demo you were getting under 4E-11 at 1Tau for your source... Actually just noticed you where in Frequency Mode, All my measurements are in Time Interval mode, have you tried a Time Interval measure ? just curious if you are getting better than 1E-10 at 1sec Tau ?

Hello Peter, been doing a few tests and I have been getting the following. The DUT is a NOS AT&T RFG-RB Rubidium standard, the HP 5370B is using the stock HP 10811A internal reference. The HP 5370B is configured for Frequency, gate 1s, display rate set full CW. Timelab is in its default condition except set for frequency, sample interval set to 1 sec, and duration 600 seconds. 1s Tau is 4.47E-11. Changing Timelab to time interval, all other parameters the same. HP 5370B set to TI, sample size 100, display rate set around the 11:30 position to refresh at about 1 sec intervals. 1s Tau is 4.11E-11. Don't know if this is going to help much since I don't use Timelab as often as I'd like. I tried different settings in Timelab such as points, minutes, seconds and set the time interval as low as .1 seconds, I got more or less the same results. However, if I left the display rate in its full CW position during TI measurements, I got results that were about 1 order of magnitude better at 100s x.xxE-12 to -13.

I have a second one I purchased as a parts unit. It powers on but the rotary encoder does not function, and the digital storage option does not seem to work correctly. I do not have an additional channel plug in, been looking for one myself. It's looking like I'll have to buy another parts unit to get one. Thanks for watching.

@@CraigPetersen12f36b Yeah same here. I'll have to spend more than I paid for the working unit just to have two more channels. ;)

Thanks for watching. Yeah, it's a pretty cool scope, unfortunately soon after I posted this video the issue resurfaced again. After going into a deeper dive, it seems that either Q30 and or Q31 appear to be failing. The reset pulse going to Q30 does not change in either amplitude, frequency or width, there is no sign that the clamping diode is leaking. So, at this point I'm going to replace Q30 and Q31. Interesting that the 3 and 4th channel module has a backup battery, the only battery mentioned in the service manual is the one in the enclosure on the back.

Sometimes those symptoms are a sign that the PLL is unlocked. In that case I would start to troubleshoot in that area first. Thanks for watching!

Unfortunately no. However, you might be able to call them and see if they can provide you a list of qualified service shops that may be able to repair this transceiver for you. You can still get replacement parts from Icom for this transceiver but no longer service it directly. If you're sure it's the PA section it may cost about the same to find one eBay and swap the entire module out. 73 and thanks for watching!

Thanks for giving some background on the development of this instrument. I have been traveling lately and haven't had much time to dive into this instrument. Thanks for watching!

While extremely limited it still is a useful tool to diagnose HP-IB bus issues. It even has a header on the back that allows you to attach a logic analyzer if needed. Thanks for watching!

I have posted the image here. photos.app.goo.gl/gksC6mUmF7UaUMz27

I just looked at the service manual. There is a section that details how to service the attenuator, but strongly suggest that the attenuator be exchanged for a new one via their "attenuator exchange program" long since gone. It may be cheaper and less frustrating to find a parts unit off of eBay.

I've been pretty impressed on how well this scope works. The HP-IB control language is fairly straight forward making setting this up remotely a breeze. I have a "parts" unit coming that has all the digital options installed, I might be able to simply swap boards and the button panel on the left to upgrade this unit, we'll see. Thanks for watching.

I tried that several times after I had posted the video, I eventually had to adjust the "zero" trimmer on the A3 board to correct it. For its short comings it's still a very useful instrument. Thanks for watching!

Hello Tom, I wasn't aware of this unit either. I bought this from a seller that I also purchased an Agilent 1670G logic analyzer from. After a quick search I found the unit listed in the 1990 Tektronix catalog, read about its specifications and features then made the purchase. It was a VERY good deal compared to the 577 and other curve tracers listed in the catalog. Since doing the video I have also tested the print function and it also works just fine. It may be limited to 100v collector voltage, but it will provide up to 100 watts of power and should be more than enough for my lab. I hear you on getting things shipped overseas, I have some vendors I work with in the Netherlands, the shipping alone is sometimes more than the replacement part. Thanks for watching, hope you find something local to your area.

@@CraigPetersen12f36b Hi Craig, that's good news that printing is working 👍 Here in the Czech Republic, it is a big problem to get testing equipment for reasonable money, 550 USD is a great price for a tracker, but it is more than a third of my monthly income. I used to own a Huntron 2000 tracker, but I lost all the equipment I had acquired in a lifetime when my workshop was completely robbed. I could buy a non-functional model 576 for approx. 670,- USD without tax, customs and shipping, but after adding it up, I came to a price of around 2,200,- USD and that was absolutely unbearable for me - today only an amateur. In addition, some models from the 57x series had big problems with the HV transformer (I think they are transformers in the brown version), so there is a big risk that you will buy an almost irreparable device for that crazy money. I know another model that is similar to yours, but it is a Sony/Tektronix license with the model designation 370, if I remember correctly it is produced in versions - 370 / 370A / 370B - I even found it functional for sale for absolutely (for me ) absurd price of 18000 USD. While looking for a new tracker, I came across an individually modified model 577 that had an additional interface for communicating with a computer for data storage via USB. If my information is correct, the 576 was not originally intended for direct sale, but was developed solely for the development and service needs of Tektronix and later somehow found its way into the market. In the range of 1500V, it supplies a current of only 100mA, but at 15V it is able to generate up to 10A. Currently, the best available in trackers is Huntron's Model 3200S with two independent A+B inputs with G1/G2 and two IDC-64 sockets allowing up to 128 direct connection combinations. Nice day 🙂 Tom

With all the HP, Agilent, Tektronix and Fluke gear that I have, I have only run into a capacitor issue twice. An HP 3437A and an HP 5328A that had a power supply over volt failure. While I was taking the 5328A apart, I discovered that the main power supply filter caps were only now just barely starting to show signs of leakage around the terminals. Prior to that the 5328A was working just fine. That's pretty good run for something that was built in the late 70's to early 80's. I have yet to run into an issue where there was leakage that resulted in trace or some other board damage. Most of the equipment that I have had been serviced in the last 5 to 10 years, however I do inspect the filter caps and check the power supply voltages on the units that have missing, broken or old anti-tamper service stickers. Thanks for watching!

@@CraigPetersen12f36b one exception are the RIFA caps. These have almost always a cracked case and usually have to be replaced.

Thanks for the offer. I originally wanted to find a HP 8920A or Motorola R2600 series communications analyzer, but they were either priced higher than what I was willing to pay for, had seen rough service or had a number of faults. So I settled on purchasing discrete instruments instead of buying an all-in-one solution. I may re-visit the issue down the road, but so far I'm satisfied with the current setup. Thanks for watching!

Yeah, I thought about doing that since now I have the proper risers so I can get to all the test points on the cards. But since I have two functioning 3335A's the parts unit will just stay that, a parts unit. Other than the cabinet, missing hardware and the malfunctioning card I swapped out, the rest of the unit, front panel, CPU, attenuator, power supply, frequency reference are all still good. Thanks for watching!

I paid about $550.00 for this unit. 576 and 577 model curve tracers usually fetch $600+ for non-working and over $1000 for working units, however these units can produce test voltages of up to 1500v. This one goes to 100v which is fine for me. I really like the units compactness, another is the ability to store as many as 12 presets and print screen captures. Thanks for watching.

Thanks for watching! I'm certainly going to be able to take advantage of this unit, way more versatile than the cheap component testers I have been using.

Typical current draw for a stock AT-6666 running full power on FM is about 7.5 amps. I don't recommend using the cigarette lighter plug for anything over 5 amps. The center contact can have fairly high contact resistance and may present issues for you. I use the "Littlefuse add a circuit" pigtail and draw power right from the fuse box that's inside the cab of the vehicle. In any case, I would recommend a 10 amp fuse. I use a 50 watt 2 meter rig in my mobile and have had no issues. Thanks for watching!

@@CraigPetersen12f36b Thank you for the response!

Well arn't we the "hot house orchid"... But seriously. We understand you Jedi! A 576 was clearly created by the gods I would trade the future generation's youth to possess one (especially since it's of no use to me:). Cheers young Jedi 🖖Live long & prosper

Mos cert, the 571 looks like a better choice for people with more urban apartment sized benches :)

@@splitprissm9339 speak for yourself! I'm in Philly and I'll always make room for my 576 😂

Hope it helped, it took me a week or two to track down all the software I needed to install. While National Instruments no longer supports Windows versions earlier than 8, you can still download all their older software from their FTP site. download.ni.com/

Glad it helped, I have only come across this issue once or twice over the 4 to 5 years I have been purchasing used gear. At first, I thought it was a cold solder connection but was relieved that it was just a lose jam nut.

Thanks for watching. I haven't serviced this unit yet and it is still on my "to be repaired shelf". I was just thinking about this unit the other day, I was able to find a N step loop card for a good price and swapped it out with the card that I suspected may have some sort of fault. Unfortunately, it didn't change and was still displaying the same issues. I also suspect that the fault may be in the summation loop since there are two VCO's on this board and one of them may not be locking properly. I was able to finally find some riser cards for this instrument and I am just waiting for them to arrive.

Interesting, I just sold mine at a hamfest last week and no longer have the unit. You may want to look at the BFO circuit and check that it has been adjusted properly. This may be the reason it appears to be receiving on the wrong side band. Thanks for watching.

@@CraigPetersen12f36b Thanks for the suggestion Craig, I noticed an adjustment in the tuning instructions where you have to select the second of two peaks when aligning the radio so that might be it.

This meter is only designed to measure continuous carrier signals. It will measure a modulated signal but the readings will be erratic. The only HP power meter that I know of that is designed to measure PEP power is the HP 8900C. This meter is an older analog style and takes older power sensors that can be difficult to find. Thanks for watching.

Good Morning, I purchased the filters off of eBay, the prices were about $125.00 or so each, about what they were new. These filters made a big difference on crowded bands and have breathed new life into my 706MkIIG. I have the CR-282 high stability option but have not installed that option yet. The last module I plan on installing is the speech module that announces operating frequency and mode.

I do remember hearing something about this back in my early days but cannot recall anything recent. Yeasu made many variations of this rig so I would imagine you could eventually find something. Thanks for watching.

@@CraigPetersen12f36b I've thought about using a super capacitor instead of a battery but since I don't use it that often I don't see a good reason to modify it. I have an Icom 290a that has the same issue.

Yes, the first 10% of the scale is ungraduated for this reason. The service manual states that the meter movement will typically rest within the first 20% to 50% of this ungraduated region when operating correctly. Thanks for watching.

I didn't have a powered speaker on hand that I could hook up for this demonstration. Thanks for watching.

@@CraigPetersen12f36b I'm just now learning and getting into testing equipment so at the time of that question I genuinely didn't know whether that had audio out or not - I've learned a lot in the past week!! thank you for being a part of that journey