1:22 The Why cable. Is that the one used when shouting at the circuit going why!? why are you not working? ;)

I used the prior generation of this product in 1985 when I was working for Raytheon as a High School intern (!). We were going SNA over SDLC and BiSync - and used this to monitor SNA handshakes to a 3270 product for the airlines. It brings back the Memories!

@andrewallen9993

2 жыл бұрын

Syn syn syn enq!😁

When I worked as a Systems Engineer at HP in the 80s, I would sometimes use a version of this to troubleshoot mis-wired and mis-configured serial connections. It made the job a breeze. Loved it!

Some interesting HP trivia at 11:22. The power supply has “Yokogawa” printed at the upper left. Yokogawa was a Japanese company that HP had a joint venture with for many years. Lots of products came out of “YHP” as it was called. I wonder if just the PS came from YHP or if the entire 4957A was designed and manufactured there. I don’t remember. Maybe someone else knows.

@reinoud6377

2 жыл бұрын

AFAIK Yokogawa still exists

My old buddy - helped me to debug the HDLC modules I coded for the fibre optic Remote Integrated Multiplexers that where dotted all over Australia for decades supplying ISDN and POTS services. Those terminal features where useful for debugging the VRTX based code too :)

Hi Marc, I am incredibly jealous - I bought a faulty one off e-bay hoping it was a power supply issue - well it was but the power supply was blown because the RS-232 port had been hooked to mains! That pretty much blew out everything on the 12V lines - so the floppy drive is dead (stepper drive blown) the power supply had the same fault with the start cap as yours, but when I fixed that the PSU exploded. The vertical scan was blown and the RS-232 line drivers and interface board were destroyed. Note - a video will come! In debugging the system I have found a lot - the video is handled using a dual-port RAM from IDT - this is big enough for the 80 column mode - on the machine that is playing up in 80 column mode, it could be worth having a look at the input and output address lines and data lines - that could give clues as to where the fault is. It may just be the IDT RAM has an issue - in which case it is a simple switch out is possible as it is a PLCC soldered onto the board.

@BogTheWombat

2 жыл бұрын

Mine appears to be an early version - it does not have the 80 column VT100 emulator firmware. So maybe the firmware was rushed out to get the unit in the field - makes me wonder if there was a serious supply problem with the older version.

@CuriousMarc

2 жыл бұрын

Oh no! Looks like I took all the eBay good luck from you! Still took me two tries. We should definitely try the simple RAM replacement if it's socketed.

@BogTheWombat

2 жыл бұрын

@@CuriousMarc not socketed but not fine pitch

@MatthijsvanDuin

2 жыл бұрын

mains on RS-232 ? sometimes you really wonder wtf people do with their gear. When I worked for a company that created DMX-512 (RS-485 based) lighting controllers we once got one returned for repair where we discovered the varistor that was protecting the DMX-512 output was just... gone, a scorched crater left in its place. o.O

@BogTheWombat

2 жыл бұрын

@@MatthijsvanDuin It is the only way to explain the level and nature of the damage. It is amazing the number of people who should know better but don't. A few years ago a customer returned a sub-station control computer complaining it was faulty out of the box. When we opened it every board was either burnt or was smoke damaged. Somebody connected it to 380V not 230V. Varistors do burn well and smell bad - and when you have 20 or 30 of then all overloaded hilarity ensues!

@9:38 - "...as a historical side note..." We come to expect nothing less, fine sir.

Went through many airport check-ins with on of these as a carry on. Once, I had to demonstrate that it powered up to security, and it fell all the way to the floor. Still worked!

I see. The version we used was the earlier one with the breakout box in the cover. Great help while diagnosing problems. I must have resoldered hundreds of those power supply pins that cracked. The first ones cracked again, so I changed to cleaning all the solder away. Then I wound an inch or so of 24 AWG bare copper wire around the pin with a tail running into the PCB trace. Never had an intermittent problem again after that. 👍👍 Thanks for another great video, Marc. Stay curious!

Sorted so many problems with this instrument in the day. Toolkit in one hand. Analyser in the other. Ah. RS232, what a protocol. Happy memories. Thanks.

In the 90's I ran the ICL training course for OSNET and needed a mainframe to connect to as a server. That was impossible in a classroom so a wrote a C03 protocol emulator on one of these using the basic scripting function. And it worked enough to show a simple menu from the M/F. I also fixed numerous issues for customers with it. A wonderful piece of kit.

It was decades ago but I used one of these to troubleshoot RS-232 communications for test equipment I designed for production test of aircraft flight data acquisition units. It really helped.

Gosh I would have loved to have had something like this back in my ISP days in the 1990s, would have made my job so much easier.

Yeah! Used this in the 1980s to debug X25 and other proprietary protocol implementations I was doing on a PDP11/RSX11 edit: It must’ve been the earlier version as it was around 1983ish

Enjoyed the video! I have a 4952 and used it to debug more serial protocols than I can remember. Super handy tool.

Nice work as always! Interesting with the ROM swap. The starting cap I had to replace in a PSU recently too and learned about that, nice with older switched PSU's because there simple enough to visually figure out what they do.

@Derundurel

2 жыл бұрын

Funny, I had to replace this capacitor in a terminal power supply recently. In my case and in the video, they are both mounted next to hot components. The failures were almost certainly caused by heat.

Have one of these and still use it a lot now - many industrial machines still use 232 or 485 etc - Great piece of kit :)

Magic fingers, beeps of joy, and working electronics! It's what Saturday mornings are made for 😊 Oh, and sofas & coffee 😉

many fond memories of this protocol analyzer some 35 years ago, when our network was RS232 and modems based (4800bps, bisync protocol)

I used to work with a flavour of this a lot back in the '80's. Ours had a kind of pod thing that covered the keyboard when it was folded up and it then became part of the case. Once removed the pod could be velcroed to the top pouch, attached to the rear panel with a multipin connector and the pod presented the breakout above the screen. Never seen one with the BOB on the side. Very expensive bit of kit back in the day.

I just love this channel. I'm a mechanic and know only a few basics about electronics and protocols. And what I also love about this channel is the comments and the informations that you find there. Hope you add magic fingers and beards of wisdom to your shop soon :) Greetings and best regards from germany.

Oh my. A blast from the past. I remember using these to debug X.25 and serial comms in the mid 1980's, installing Vaxen and PDP-11 network devices for an oil company. Lovely to see them still working.

Great work! I've got a pair of the 4952A's that I picked up to do Bit Error Rate testing on old analog modem circuits or their modern digital equivalent (Term Server - Cisco Router - T-1 Line - Cisco Router - Term Server). You would think that the digital equivalent would just work but there are various T-1 timing options that can be misconfigured in the routers or by the T-1 provider in ways that can result in mangled data just like we used to see on old analog modems.

@TheFool2cool

2 жыл бұрын

Glad to see I'm not the only one battling obscure T1 timing issues that nobody seems to understand anymore

@bobjohnson904

2 жыл бұрын

@@TheFool2cool My low-level headache from my flu shot finally subsided so I thought I'd punch up a quick YT video. Now I'm mired in horrible T1 clocking memories (internal, line, loopback tail circuits) and my headache's back. 🤦

@bobjohnson904

2 жыл бұрын

Dedicated leased 4-wire analog multi-drops! DO NOT send a loopback tone to trouble shoot or you'll isolate a half dozen sales offices!

Excellent. I have one of these and have used it a number of times to analyse data streams but Im embarrassed to say I didnt know it could do VT100. Im going to try mine out now. Mine looses its setup and I assumed it was the batteries but I was a little scared to change them, now I've seen it can be done I'll do that too. Thank you

@CuriousMarc

2 жыл бұрын

There is a catch though. If you have a 4957, the VT100 emulation is resident in ROM. But if you have 4951 or 4952, the VT100 emulation must be loaded from an application disc, which is a bit of a pain to recreate.

@Derundurel

2 жыл бұрын

Even if you don't get around to replacing the batteries, it is a good idea to clip them off the board. They leak, and cause a lot of corrosion damage.

@campbellmorrison8540

2 жыл бұрын

@@CuriousMarc Yes I have a 4957A and just tried it, and its the 32 CHR FW but it works thank you

@campbellmorrison8540

2 жыл бұрын

@@Derundurel Excellent advice I will do that thank you, nothing worse the leaking batteries

@CuriousMarc

2 жыл бұрын

@@campbellmorrison8540 Oh you have the 32 char or whatever low resolution mode too? Then it's not just me. What does the rev and year of your firmware show on your startup screen?

Ah the HP4951. Brought back lots of good memories. Used it extensively during the 90's to develop and debug controlling machines for assembly lines. The external breakout panel that you mentioned is actually the front cover, once the keyboard is folded up. It was only in the later models that they integrated the breakout panel into the chassis, like this HP4957.

This is a fascinating video. I always learn something new when watching your presentations! Thanks!

Never go full electroboom!

I saw this unit in one of the central offices I visited. It was connected to the rack, I think to control and monitor the old tel exchange or data circuits to customers. This was a neat video for me to see, thank you. These are really powerful units for their time.

Can we talk about Marc's shiny red house coat? Is he hosting Masterpiece Theater when not salvaging electronic treasures?

In the 1980s, each time you needed to connect a new pair of computer and peripheral device like a terminal or printer via a serial interface, the game started over form new. Our rule was: you need a solder iron, an oscilloscope, and an hour of time. We had additional gadgets like back-to-back soldered D-Sub connectors with blank wires in between to hook up the probes. There were so called "null-modem" cables, crossed cables (crossing TX/RX and possibly also DTR/RTS), and all kind of gender changers. And of course there were the 25-pin and space saving 9-pin versions of the D-Sub connectors. What a mess. It was easier if the devices supported the Xon/Xoff flow control, then you could get away with just three wires, you only needed to get TX/RX correctly connected. Not yet 20 years ago, I designed a test adapter for SCADA systems that ran serial protocols over optical fibers. The adapter consisted of two optical/RS-232 converters which could be combined in tap mode to sniff the communication between the real devices, or the converters could be used independently for simulating either end device in such a system. The processing was no longer done in such a device like the hp 4957A, but with a software running on a PC. The product has been discontinued years ago, but we still get occasional requests for the test adapter hardware.

@CuriousMarc

2 жыл бұрын

Well said. RS-232 in a nutshell. No matter how much I try, Rx and Tx are always inverted the wrong way, I end up with two males facing each other, one is 9 pin and the other 25, and hardware handshake freezes the whole thing :-D

@stargazer7644

2 жыл бұрын

@@CuriousMarc It really wasn't that hard if you worked with it a lot, you just had to know the signaling and the ways it was commonly used. I did a lot of serial troubleshooting back in the day. A few minutes with a breakout box and you knew exactly what pinout you needed for any cable. I also used one of these protocol analyzers to decode x.25, baudot and bisync on both async and sync circuits for many years.

I was just using one of several 4957As that I have at work, for testing RS-232. I also have a "newer" module -swappable test set that is no-where near as functional as the 4957. Thanks for this video.

11:49 Master Ken wants you to stay alive to do more awesome cooperations :)

Nice video to watch while family is sleeping 😊 Sometimes things just works out. Would have been awesome if the RS332 was invented with auto configuration of RX TX- I often end up mixing the RX TX up when doing cables etc :-) ❤️RS233 All the best from Denmark

I have a love for the old HP equipment, made by engineers for engineers. Sometimes even barebones, but every function had a use and every use had a function. While e.g. scopes from Tektronics were almost overly elaborate, HP kept to its swim lane and made excellent tools for the everyday use. Not too keen on the Agilent days, but as Keysight they seem to have found their focus again.

In re networking on serial ports, as I recall this is how the original AppleTalk worked. On my Macintosh Plus, the AppleTalk socket and the serial port were exactly the same.

@CuriousMarc

2 жыл бұрын

Indeed, I think AppleTalk used RS-422 for its networking (same as RS-232 but differential, can go through longer cables).

Used these daily (4952a first) for nearly a decade and eventually ended up just looking at the flashing lights to find errors. Lots of repetitive transactions which is why flashing lights were useful. Lived in nearly all of these protocols. Seemed complex then but today is very simple compared to what kids experience nowadays.

This takes me back. This was something we had at work back in the 80s and used to use all the time.

Loved that box back in the day.

Ah the 4957, solved many problems with one of these. Was my go-to tool for anything serial.

Awesome video as ever, Marc. Those yellowed spacebars are bad for my OCD, though... I'd be happy to retr0bright them for you!

The first thing I always try to do with those old machines is to look up if Noctua has a matching super silent industrial fan and replace them.

@Mythricia1988

2 жыл бұрын

Same. Although it should be said, these quieter fans rarely move the same amount of air - more air per dB of noise, sure, but still less overall airflow. In most cases this is not an issue at all, but I've had it bite me in the ass a few times, where the new quiet fan wasn't quite able to do the job.

Oh wow, I would have loved to have this for a project I just finished up! Seems very useful

I am pretty certain our electric utility used two of these with our SCADA supervisory control and data acquisition RTU remote telemetry units comm lines.

wonderful video, we have a HP 4951A in our lab. that is still good if it is needed for a task.. thanks a lot for the interesting walk around...:) 😊 👍

This was great, I didn't realize that these had so many processors either. I have a couple of the 4952A models that I rescued a number of years back from being thrown away that I've never used. They don't have the cable sets and are the model Marc referred to that has the rather clunky interface connections on the lid vs the side. Who know why they made such a drastic change. I'd love to see them working again someday just for fun. It's not too often that [old] protocol decoding for serial communications needs to be done but I hate to see stuff like that abandoned and thrown away. This stuff was great and back when HP made some of the best test equipment in the world.

Perfect. Just take what you get with the given hardware. Plus some recapping to get it working at all. Thanks for sharing ! :-)

I thought step 1 on old HP equipment was always before even turning anything on SAVE ALL THE ROMS with an EEPROM reader. At this point it's good fortune they even work at all.

For once a repair that went smoothly. Well done!

Alright, another piece of equipment to go on my ever-growing wishlist... Love these repair videos.

Oh, what better to do at 2:20EST!

The character overlap may be caused by a degraded capacitor in the horizontal width circuit on the CRT. There may be a width coil you can adjust, but by making the image wider (like it originally was), I doubt you'd get the overlap. Looks like an analog issue, not digital.

As always, lovely job. They have fancy floppy drives, I haven't seen ones with cutouts there before.

We used these in the 90s to debug the serial devices that car manufacturers required our computers to talk to. Believe it or not, sometimes the specifications they gave us weren't exactly correct.

You can run diffs between binaries using Ghidra

It's a good machine. I have one and last "used in anger" as recently as last year for working on a medical laser of similar vintage... modern USB-RS232 dongles didn't work with it. (Eventually we found a fancy industrial one that did, but the HP serial protocol analyzer was still very useful figuring out the settings and some of the protocol.)

It’s a wonderful thing when you buy a parts machine to try and make 1 good unit, when the parts machine only needed minor repairs and you end up with 2 good units!

If you're interested in alleviating your lack of spot welding equipment, the cheapest reliable/quality solution I've found is the kWeld. Paired with a commodity high-current RC hobby lithium ion pouch battery it produces reliable welds and is tunable from the very lightest terminals/strips up to pretty beefy stuff. Not dirt cheap (a couple hundred bucks plus the battery to drive it), but I tried other cheap aliexpress specials before and they blew up in my face on the first weld attempt so don't bother with anything lower-end.

When your parts machine winds up being better than your main machine. LOL!

Oh wow. This beings back serial debugging memories.

A marvelous toy I last used about 40 years ago!

cool machine, I travelled with that kind of device aroun europe well before laptops. used that as a terminal and also to debug protocols. Used also texas silent, but with bubble memory 😁 and integrated 300b modem... that protocol analyzer phased out later on because it has quite low max baudrate....

@ristojokinen1258

2 жыл бұрын

machine I used was 4951 (19200b)

Wonder if this would be of any use for troubleshooting HDLC interfaces on NEMA TS2 traffic signal controllers. They use HDLC to interface to the loop detectors, conflict monitor/malfunction management unit, and the load switches for the signal heads.

I got the NavTel 9460 Plus in brand new condition. Those are neat units, this one is RISC based and got an Harddisk built right in too.

Fixed a few VT-100's back in the day =D Not very many though, most of the terminals I came across were manufactured by Wyse. Great job getting both of the 4957 working =D I hope you can later work out why the high res mode is borked.

It looks good. It beeps. It's beautiful. I want it.

Imagine a channel where its just these 3 guys literally fixing the practically impossible to fix. The channel name could be "Practically Impossible Fixes"

I used these analyzers early in my career for Async, Bisync, SDLC and HDLC analysis. However, I always preferred the Atlantic Research Interview Line of products over the HP analyzers. I spent many years in the office and in the field doing debugging, mostly with the AR Interview 932 model. At least for me, the AR units were simpler and easier to use that the HP ones.

Got HP 4951C for review 😀 With all cables, Floppy disk with utilities and connection board of cource. And yep - It's definitely cute

@CuriousMarc

4 ай бұрын

Good luck with it! The 4951 with its traditional logic is a lot more hackable than the 57 with all the FPGAs!

@ArtemKashkanov

3 ай бұрын

@@CuriousMarc Yep. but after some research I fount that binary format for apps is incompatible with 4952 and later models. So I could succesfully upload apps from utility disk for 4951, but still can't build my own - Need to have some sex with IDA Pro to find out entry points addresses.

I have one of these, and it also has the lower resolution mode for the vt100 emulation, which has always bummed me out since i wanted to use it as a cool looking terminal.

It even has EBCDIC. Nice thing to have. I was not expecting FPGA in such old gear.

I would be nice if hp and other manufacturers released schematics and service information, at least for these old pieces of equipment

Ah, serial comms.....happy days(!). Used to work at a place that did training and was asked to make a wee box to spit out "The quick brown fox...." endlessly to torture students. Used what was at the time a pretty neat chip, the TMS7782. Used the same chip to make a tape position counter for reel-to-reel studio recorders that output in Braille...but I digress.

Could have used one of these at work last week. Was trying to troubleshoot a communication problem to a lab machine. Eventually determined that when the PC's power supply failed, it apparently fried the UART on the motherboard.

I used one of these back in mid 90's to trouble-shoot X.25 traffic blast for the past...

Congratulations

Mr. magic finger than, magic probe now,

I have the exact same VT100 here. I believe it has a 8080cpu.

OMG haven't seen one of these since I sent like 50 of those to Dove Bid about 15 years ago when I worked for Intel. ;-)

I would make software changes to a modem and sweat the BER Bit Error Rate results with the 511 pseudo random sequence. It was a harsh and unfeeling but fair judge of my software effort.

Marc, try ESC # 5 and ESC # 6 escape codes on these machines. The first is "single width line" (80 characters) and the second is "double width line" (40 characters). They may or may not do anything useful. There is also an escape sequence for a 132 character line.

@CuriousMarc

2 жыл бұрын

That does not do anything on mine.

Humerously I actually had a VT100 arrive here the other day, which is my own next restoration project.

Verry interesting stuff

Oh my, this is such a cutie. I want to adopt one 😀 I have no idea what it does, but nevermind. :)😀

Very nice result! Reminded me of my repair of a 4952A. (Does the 4957 also have this stupid red keyboard connector?) Looking forward to Eric's reverse engineering results. ;-)

@BogTheWombat

2 жыл бұрын

It is a ribbon cable onto a standard DIL header

What is the technical term for ( at start up if nothing happens use several fingers to activate many switches or buttons)

шикарный аппарат!

How were you able to work out that C7 was the capacitor to replace on the PSU? I'm guessing that either you were able to reverse engineer it or it's the same PSU design as the older devices. Thus did have a schematic available.

@semifavorableuncircle6952

2 жыл бұрын

Its actually the easiest fix. Switching PSU that doesnt want to start or always restarts, 90% of the time its the small 10-100uF electrolytic on the primary side that also has a 50-500k resistor to charge it up from the high voltage bus. usually the cap goes bad, sometimes the resistor also goes up in value if it runs too hot.

To me the battery seems just 4S1P (unlike 14:24 audio says a serio-parallel), and the vertical joints extend to a solder pin purely for mechanical reasons

@CuriousMarc

2 жыл бұрын

Could very well be.

Is there a computer program that would allow something similar? And can you control Ring port from c?

I have one of these, but it looks a little different. It doesn't have the interface on the side. It was a separate piece that acted as a cover over the folded up keyboard and contained the breakout interface and connected to the main unit with a large DB cable. DB37 maybe? It was instrumental in product development that allowed me to start my own company in the early 2000s. Edit: Ahh looks like miine is a 4952..not a 4957.

@CuriousMarc

2 жыл бұрын

You have the earlier HP 4951 or HP 4952 that I talk about in the video. Nice machines too!

but where are the firmware files that you backed up?

@CuriousMarc

2 жыл бұрын

It's on my website as usual, link in the description. Did you have trouble finding it?

Finally a good portable Rpi4 case!

Nice!

That's great. Now you have a terminal to connect to the high resolution machine. Win win

Marc would it be possible to copy the newer firmware onto eeproms so both can do 80 columns higer res ?

What is that floppy disk format in those drives - LS120?

@semifavorableuncircle6952

2 жыл бұрын

Standard 3.5" DD floppy. Uses a proprietary HP format, not pc compatible.

Now that was easy.

I like pretending I'm one of the crowd ... like flying a cardboard rocket ship when you're 10. Wow that was a long time ago.

yes, new video. :) greetings from slovakia

@CuriousMarc

2 жыл бұрын

Greetings from California!

Could you do a Vlog about Håkan lans on first color graphics machine!! 🇸🇪👍