[time-nuts] LH Question
As backup I installed LH 5.0 on a laptop with Windows 7 Pro but no RS232. I inserted an USB to Rs232 adapter and it recognizes it as com Port 6. LH shows no com port. How can I switch it to com port 6? Thanks Bert Kehren ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Dead 5065A - Some comments - Some questions... (II)
Luciano, Yes, the ovens in the cavity are working correctly. What destroyed the 5065A in the first place 1988 wasa very high raw input voltage approaching 40V(something wrong with the AC Xformer that possibly caused the original cavity windings to short circuit ?) I got help from Corby Dawson how to repair that cavity but some timeafter the repair, the magnetic field winding went open circuitand not finding the fault location, I could not repairthat cavity one more time. The oven I am using nowcomes from the second unit. It was not faulty and also equipped with a TED. The resistor value labeled on its case has been appliedto the regulator circuit. After warm-up the readingson the Circuit Check meter is < full scale. If a voltage transient may appear on the +20V, then Iwill consider some sort of over voltage protection. Also of course replacing the 20V board with the improvedversion besing discussed here some weeks agowhen/if it becomes available. All the best. Ulf Kylenfall ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Dead 5065A - Some comments - Some questions...
..Continued. Having discovered that the A3 multiplier went bad the firsttime after a few hours of service, I checked the A3 unitfrom a scrapped 5065 on my bench. It was neverinserted in the once working unit : DOA The problem with some of the plastic packaged FETs wasthe same. Also that output transistor was bad. That 5065 was salvaged from a shed somewhere. Previous ownertook out the 5MHz XO and I remember that there had beensome unsuccessful attempts by previous owner to openthat A3. (I take it that he eventually gave up, took out the5MHz XO and discarded the rest.) I am therefore of the opinion that either there is a reliabilityproblem with these transistors due to microcracks in the plasticpackages allowing for moisture to reach the silicone waferor long term silicone deterioration that gets accelleratedby applying supply voltage to them again after 30 yearsor so. I have experienced similar problems with other oldinstruments that is powered on for the first time in 20-30years. And I do not mean the RIFA power line capacitors that more or less always let out their smoke... +20V is rock stable. I will of course check if there are anyunstabilities once all modules are back in place. The 2N4416 that was previously used as a replacementin my unit did work OK. The output transistor as well. And - also the 3N128 - That one is TO-18 hermetic... About A1: it seems that SN74176 (or possibly 74196)is a replacement for the 1820-0322 - Signetics N8280N. It can not be so difficult to find a modern replacement/modification for the 1820-0315 one-shot should it be necessary to build a completereplica of the synthesizer. Cheers. Ulf Kylenfall ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Dead 5065A - Some comments - Some questions...
Ulf, The A1 modules are most likely OK. They do not need stellar performance for the 5065A to easily beat spec. The A3 modules are another matter! If you are indeed feeding them with 1VRMS and can't get a good output at J8 then something is not right! HP made several versions of the A3, the series 2644A was the last and was completely redesigned. It is much more reliable! I've mentioned this before, the ceramic tuning caps seize up and you MUST break the rotors free before aligning the module! If you don't you will most likely break the rotor connection! If they don't turn with MODERATE pressure they need attention. If the rotor slotted shaft turns but the rotor does not it broken! Replacing them is a pain so again break them free first. Using a stiff plastic shaft lever or push horizontally at two spots 90 degrees apart listening for the rotor to "snap" free. Once you can get the proper A8 RF level the bias pot and matching network needs to be tuned. I usually just put the variable inductor slug 1/8" down from the top of the form and just leave it there. Cheers, Corby ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 193, Issue 36
Hi Normally the parts I am looking at are the run of the mill eBay parts. They are < 10 years old, but have been on boards. It is rare that they will not tune to frequency (if they have output ….). My guess is that the typical modern OCXO is good for 20+ years before they age out of spec. Bob > On Aug 24, 2020, at 4:47 AM, Dave B via time-nuts > wrote: > > Of course, they may be pushed out to the surplus market, because they > have aged/drifted out of spec, before they were removed (however that > was done) from their original host equipment. > > But junk box storage is often "less than optimum" for lots of stuff, not > just oscillators and crystals. > > 73. > > Dave B. > > > On 23/08/2020 17:00, time-nuts-requ...@lists.febo.com wrote: >> I?ve tested a lot (like hundreds) of surplus OCXO?s. Well under 10% of them >> met their original >> performance specs. That?s just for the stuff I can test in the basement, >> with better test systems, >> the total would be lower. > > -- > Created on and sent from a Unix like PC running and using free and open > source software: > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 193, Issue 36
Of course, they may be pushed out to the surplus market, because they have aged/drifted out of spec, before they were removed (however that was done) from their original host equipment. But junk box storage is often "less than optimum" for lots of stuff, not just oscillators and crystals. 73. Dave B. On 23/08/2020 17:00, time-nuts-requ...@lists.febo.com wrote: > I?ve tested a lot (like hundreds) of surplus OCXO?s. Well under 10% of them > met their original > performance specs. That?s just for the stuff I can test in the basement, with > better test systems, > the total would be lower. -- Created on and sent from a Unix like PC running and using free and open source software: ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Dead 5065A - Some comments - Some questions...
Ulf, what you write and that you have found several dead transistors the problem could be derived from the power supply. When changing transistors and you did the calibrations correctly the HP5065A still does not work means that the initial fault was not found. The first question that comes to mind is if the two ovens of the physical assembly are working, you can check this from the meter on the front panel. Anything is possible but it seems strange to me that you have two bad A1 assemblies. There are many variables about this repair. Luciano Luciano P. S. Paramithiotti tim...@timeok.it www.timeok.it Da "time-nuts" time-nuts-boun...@lists.febo.com A "Discussion of Precise Time and Frequency Measurement" time-nuts@lists.febo.com Cc "Ulf Kylenfall" ulf_...@yahoo.com Data Sun, 23 Aug 2020 21:06:06 + (UTC) Oggetto [time-nuts] Dead 5065A - Some comments - Some questions... Greetings. Having had my 5065 disconnected several months due to all sorts of things, and started it up yesterday. It was dead. "Pining for the fjords" No 2nd harmonic. Just PhotoCurrent. Quick Phase Checkusing a scope in X/Y-mode returned a "U" instead of a bump And most of the rest was noise. I have previously replaced a number of transistors in A3 (5 -> 60 MHz Multiplier) during first attempts to resurrect this unit and it seems like the rest of them were gone (how come?) now. Many of them are 1855-0327 which I have replaced by 2N4416. Q7 by BC557 (!) and Q9 by 2N5109. After this, I have adequate regulation and an AGC of > 4V. All-in-all: Just about every transistor in A3 was bad. There were output at first ~ 10 dBm at J8 but it was not possible to increase the output by tuning. Also there was no AGC. I checked a second unit from a scrapped 5065 on my bench and the situation was the same with that A3. Low output power. No AGC. So now for the question before I put any more energy in trying to fix the rest of the old faithful: I checked the A1 syntesizer unit which did provide correct output frequencies but they were not as stable as the internal 5 MHz Osc. (10811) HP does not mention any stability/jitter data for A1. Using a 5370B and 1 second gating, the output fq was stable down to single kHz figures but jittered further down. The 5370B counter is locked to a GPS diciplined 105B and comparing with the 5065's internal 10811 (in OpenLoop mode), that oscillator is also very stable and settable within spec. I have two of these synthesizers, but they are both the 1st edition using TO packaged IC's that are unobtanium. One of my manuals shows a more modern unit with plastic DIP's. Some signetics and a one-shot that is unidentifiable. IF the A1's are bad - has anybody made some reverse engineering trying to fit the "DIP-version" with modern available IC's or modified it in a way that can be reproduced? Best Regards Ulf Kylenfall SM6GXV ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
