BTW: The HP firmware programmer must have smoked something silly. They coded a simple negation for the head select as follows (CL contains 0x00 or 0x01):Code: [Select]f000:9279 f6 c1 ff TEST CL,0xff
f000:927c 74 02 JZ HEAD0
f000:927e b1 ff MOV CL,0xff
HEAD0 XREF[1]: f000:927c(j)
f000:9280 fe c1 INC CL
Can you now duplicate program disks?
Maybe the code had multi head HDD something earlier.
f000:9279 80 e1 01 AND CL,0x1
f000:927c 80 f1 01 XOR CL,0x1
**************************************************************
* FUNCTION *
**************************************************************
void __stdcall16near DISCLATCH_SELECT_HEAD(word head)
void <VOID> <RETURN>
word Stack[0x2]:2 head XREF[1]: f000:9276(*)
DISCLATCH_SELECT_HEAD
f000:9271 55 PUSH BP
f000:9272 8b ec MOV BP,SP
f000:9274 50 PUSH AX
f000:9275 51 PUSH CX
f000:9276 8b 4e 04 MOV CX,word ptr [BP + head]
f000:9279 f6 c1 ff TEST CL,0xff A little bit strange coded: head can be 0 or 1. If "no bits are set", this is head 0 and we jump. incrementing 0 to 0x01 and rotating it left two bits to set HDSEL output to 1
f000:927c 74 02 JZ HEAD0
f000:927e b1 ff MOV CL,0xff Now for head 1: CL is set to 0xFF, then incremented to 0x00, then rotated two bits, so we set a zero to the HDSEL output
HEAD0 XREF[1]: f000:927c(j)
f000:9280 fe c1 INC CL
f000:9282 f8 CLC
f000:9283 d0 c1 ROL CL,1
f000:9285 d0 c1 ROL CL,1
f000:9287 a0 fc 70 MOV AL,[0x70fc] fetch DISCLATCH_SAVE
f000:928a 24 fb AND AL,0xfb AND it with 0x11111011 (HDSEL bit set to zero only)
f000:928c 0a c1 OR AL,CL OR in the negated head
f000:928e e6 80 OUT 0x80,AL set DISCLATCH
f000:9290 a2 fc 70 MOV [0x70fc],AL and save it to DISCLATCH_SAVE
f000:9293 59 POP CX
f000:9294 58 POP AX
f000:9295 5d POP BP
f000:9296 c2 02 00 RET 0x2
I have been with this thread since page 3. And since then I have contributed literally hundreds of hours of my time devoted to test equipment tear downs, repairs, and restorations. As well as hundreds of accompanying photos. And yep, some off content stuff too. But to suddenly be branded a "bad actor" I find absolutely insulting and unwarranted.
I promise not to let the door hit on the arse on the way out.
Sorry if you feel offended by this as it was not intended to offend. Please note that my background is in network security and as such the term "bad actor" is generally referring to someone trying to break a system. I am not trying to coin anyone here as a criminal or a bad person. All I am stating is that it's the minority that do not agree that are causing the problem here (by continuing to post OT), but at the end of the day, these are the rules and no amount of arguing will change this.
I don't think it's fair to say that some have claimed falsely. There are times on here where there is some useful information, then it gets lost in pages of general rubbish, it's a shame, but it has happened.
Good grief, I go to work for a few hours and when I come back I find things have gone thermo-nuclear... whatever happened to moderation (with a small "m") in all things?
Currently waiting for some Fluke Suregrip croc clips to turn up that I got for Not Very Much. In the mean time I have to be happy with a couple of Metcal SCV-CH50 tips for Next To Nothing (have 4 NIB now, should last me until the apocalypse) that arrived yesterday and a Starrett outside micrometer, 0-25mm, that came today, for A Quite Reasonable Price.
Hopefully things calm down around here and we can get back to mostly TE posts with a sprinkling of off-topic, so the Moderators (with a capital "M") can leave us alone.Like you, I've just got back home and came online to post about my new LED displays and talk about an issue I had with one of them and hen I went out I'd had a post deleted, and now it looks like a meteoroid has crashed into the thread and left a huge crater and a mess in its wake. Before I post about my TE today, I think I'd better go back a bit and read the posts to see if I can work out the status quo around here again.
You mean this post?: https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg4375849/#msg4375849
...
Crazy how when you put something aside to work on it 'later' just how quickly 'later' can turn into years. I've done the same. Sadly, those decoders are like hen's teeth.
-PatNobody tried to build a discrete replacement? A quick look in the service manual shows that is a simple BCD-to-10line decoder, with high voltage outputs; it should be pretty straightforward way to build them, and look like there's room to mount the boards vertically in the place of the old IC's.
I was actually thinking about it today. May try to cobble something together, either to fit a 74141 (also nearing hens-teeth status) or the Russian equivalent (can’t recall the number off the top of my head), or perhaps a low voltage BCD to 10 line decoder with switching transistors, though that’d be much bulkier.
-PatDo SMD; CD4028B(SOIC-16) as decoder, PBHV8050SA(SOT-23) as switchers, 0603 R&C, and install it something like below. If you need some help, I can quickly draw something. PM if interested.
I'll get OrCAD fired up and play around with a design.
-Pat
The HP 1820-0092 decoder/drive IC uses negative logic, I believe they used the BCD 10 to 15 (no output) for blanking in some counters.
I started making a prototype based on a 74141, with a surface mount 7400 (connected as inverters) stuck on the back, unfortunately ...OT would get deleted... got in the way & it never got finished, probably lost my notes by now.
The idea was to eventually use some miniature USSR made 74141 clones I bought & the 7400 on a small surface mount board, leadframe connections would be preferable to pin headers, to allow easier removal from the HP board if it were to fail.
Unfortunately trying to make a package layout in KiCad, for the miniature 74141 clone is a problem for me, still need to properly learn KiCad. Thinking about it, it might be difficult to get the datasheet for the USSR made miniature decoder/driver IC now, don't want to get my PC hacked/attacked for looking at .ru sites (this was mentioned on another forum relating to web SDR).
Also might need several different board designs, depending on the space available, for example the 5221 has lots of space above the IC, but limited clearance to push the board into the plastic frame.
Will try an add some pictures of the bits later, can't find any on the PC.
David
Greetings fellow Test Equipment Addicts,
Back in January of 2017, when Test Equipment Anonymous began as a combination of personal reflection on my own joy of test gear, the admission by several like-minded folks of their symptoms of Gear Acquisition Syndrome, and a somewhat tongue-in-cheek parallel to more serious organizations whose names end in "Anonymous", I of course couldn't foresee just how many others were like us.
The discussion of our ailments began with a 12-step program, but not wanting to derail the thread in which it was first posted, a new thread was started for TEA. Over the next five years, the TEA thread and the TEA Glossary grew along with its community of like-minded, self-governing individuals who found camaraderie in more things than just test equipment.
Today, the TEA thread contains 20% of the posts of the Test Equipment forum. It dwarfs the size and views of any other thread on EEVblog. Clearly, the TEA community needs more than a single thread to accommodate the diversity of its members and the richness of the discussions that we have always had.
Thus, TEA has a new home at https://groups.io/g/tea and TEA Time live chat on Saturdays at 21:00 UTC will continue as before.
Thank you, Dave Jones, for your ongoing commitment to bringing electronics to the masses and for putting up with our TEA nuttiness over the years.
I look forward to seeing you all at the new TEA House.
bitseeker
TEA founder and fellow addict
however a member or 2 has a 1 week stand down so well miss their contributions until they return.
Well the almost finished prototype with a 74141 & 7400 (used as inverters for the negative logic inputs) is currently still lost. But I have just found the miniature decoder/driver ICs I bought a year or two ago, they are КМ133ИД1 (made post USSR collapse, wonder where exactly they are from ) and I did save a picture of the datasheet, needs a bit of google translate, but that shouldn't be a problem.
I already have a test board, which I built to test both; the salvaged driver ICs & the dodgy inverted number readout bulbs. I believe the decoder/driver IC fitted is the only one that works properly and yes there are several HP part numbers for these.
The test board has a 10 position BCD switch (could do with changing to 16 position one), going through a 7404 to invert the BCD, to the required negative logic for the HP decoder/driver IC, this is then hardwired a Cinch connector for a display board*, some more LEDs were going to be added for the BCD, but this never got finished.
*The little display board is from a joblot of boards bought about 15 years ago, whoever scrapped all the equipment cost themselves a lot of money, as several of the others were from a quite scarce & early electronic calculator.
P.S. it's interesting to see the other ideas for making replacements too.
Edit: Just done a google image search & download some pictures that should give all the info I need on the КМ133ИД1 IC.
David
however a member or 2 has a 1 week stand down so well miss their contributions until they return.
Lest some jump to conclusions that aren't warranted I'd just like to point out that willing silence is not evidence of forced silence. There are a significant number of people who were not given a "time out" who are taking a big step back. Just because you don't hear from some people, don't assume that they were sanctioned.
I know, it's kind of pointless designing something using those KM133ID1 driver ICs, but I would like to use the five I bought (cost $20 including P&P in 2020). The seller I got those post Soviet era (1992 made) ICs from is on holiday till 2031 (for obvious reasons), the only miniature versions available now are the older ones in a ceramic package, with a nice conductive back.
There are several completely incompatible decoder/driver ICs used in old TE including; the 74141, the HP 1820-0092 and the uLogic 996079.
David
BTW: The HP firmware programmer must have smoked something silly. They coded a simple negation for the head select as follows (CL contains 0x00 or 0x01):Code: [Select]f000:9279 f6 c1 ff TEST CL,0xff
f000:927c 74 02 JZ HEAD0
f000:927e b1 ff MOV CL,0xff
HEAD0 XREF[1]: f000:927c(j)
f000:9280 fe c1 INC CL
Can you now duplicate program disks?
Maybe the code had multi head HDD something earlier.
I can now run the applications from the disc images, yes. And write data and menus to them as well.
Regarding the code multi-head: That will not work, as there is only one bit in the DISCLATCH register for head selection and the function directly sets it.
And if you check the code:
CL=0 -> JZ HEAD0 -> INC CL -> CL now 1
CL != 0 -> MOV CL, 0xFF -> INC CL -> CL now 0
After that the code ORes the CL with the previous saved contents of the DISCLATCH and outputs the result. So it sets/unsets bit 2 for the head selection.
I alwas thought x86 assembler is uninituitive and I have avoided to look at it if ever possible, but even I can imagine easier and clearer ways to handle this negation(AND CL, 0x01, XOR CL, 0x01, ...)
My code would be:Code: [Select]f000:9279 80 e1 01 AND CL,0x1
f000:927c 80 f1 01 XOR CL,0x1
Whole code from the ROM, disassembled with Ghidra and documented by me:Code: [Select]**************************************************************
* FUNCTION *
**************************************************************
void __stdcall16near DISCLATCH_SELECT_HEAD(word head)
void <VOID> <RETURN>
word Stack[0x2]:2 head XREF[1]: f000:9276(*)
DISCLATCH_SELECT_HEAD
f000:9271 55 PUSH BP
f000:9272 8b ec MOV BP,SP
f000:9274 50 PUSH AX
f000:9275 51 PUSH CX
f000:9276 8b 4e 04 MOV CX,word ptr [BP + head]
f000:9279 f6 c1 ff TEST CL,0xff A little bit strange coded: head can be 0 or 1. If "no bits are set", this is head 0 and we jump. incrementing 0 to 0x01 and rotating it left two bits to set HDSEL output to 1
f000:927c 74 02 JZ HEAD0
f000:927e b1 ff MOV CL,0xff Now for head 1: CL is set to 0xFF, then incremented to 0x00, then rotated two bits, so we set a zero to the HDSEL output
HEAD0 XREF[1]: f000:927c(j)
f000:9280 fe c1 INC CL
f000:9282 f8 CLC
f000:9283 d0 c1 ROL CL,1
f000:9285 d0 c1 ROL CL,1
f000:9287 a0 fc 70 MOV AL,[0x70fc] fetch DISCLATCH_SAVE
f000:928a 24 fb AND AL,0xfb AND it with 0x11111011 (HDSEL bit set to zero only)
f000:928c 0a c1 OR AL,CL OR in the negated head
f000:928e e6 80 OUT 0x80,AL set DISCLATCH
f000:9290 a2 fc 70 MOV [0x70fc],AL and save it to DISCLATCH_SAVE
f000:9293 59 POP CX
f000:9294 58 POP AX
f000:9295 5d POP BP
f000:9296 c2 02 00 RET 0x2
I suppose this is generated by a compiler. At that time we[TM] used a lot PL/M-86 and the code it produced was very clear and predictable. I wrote device drivers for multi processor communication for interfacing iRMX-286 protected mode OS with iRMX-86 real mode OS, a lot of test software and while I needed some output for internal states, I accidentally invented a "GUI" for a machine on a text terminal when the customer had a glance at my screen...
How is that other copy protection, still unknown?
What is the general opinion of THANDAR TS302x series Linear Power supplies?
In the past 12 months i have picked up two TS3021 (30V, 2A single channel) and a TS3022 (30V, 2A, Dual channel, no tracking/series/parallel options), the displays are LCD displays rather than the brighter 7 Segment LED displays of the older PL320 etc series. But they seem to be a good solid design. The Dual channel PSU could do with the additional modes for series/tracking etc. But as two Isolated PSU's they are perfectly usable
The do use the same output switches as the PL series which are difficult to get hold of now.
But they sell quite cheaply on ebay and doesnt seem to have much demand? I just picked up a TS3021 for £30 + £15 shipping, but an equivalent PL320 would easily be £70+
am i missing something?
I know, it's kind of pointless designing something using those KM133ID1 driver ICs, but I would like to use the five I bought (cost $20 including P&P in 2020). The seller I got those post Soviet era (1992 made) ICs from is on holiday till 2031 (for obvious reasons), the only miniature versions available now are the older ones in a ceramic package, with a nice conductive back.
There are several completely incompatible decoder/driver ICs used in old TE including; the 74141, the HP 1820-0092 and the uLogic 996079.
David
Presumably for better heatsinking..?
Hmm, just bought a seaward PAT tester on ebay. A 2000i for £8.20 INCLUDING shipping.
I only want the flash test lead which is missing from my Supernova. It's parts or not working, but typically it probably is working when I don't care.
If you could pick between the Tek TDS320 and the HP 54602B which would you go for and why? I've been lusting over a digitising CRT scope for a while....
I know, it's kind of pointless designing something using those KM133ID1 driver ICs, but I would like to use the five I bought (cost $20 including P&P in 2020). The seller I got those post Soviet era (1992 made) ICs from is on holiday till 2031 (for obvious reasons), the only miniature versions available now are the older ones in a ceramic package, with a nice conductive back.
There are several completely incompatible decoder/driver ICs used in old TE including; the 74141, the HP 1820-0092 and the uLogic 996079.
David
Presumably for better heatsinking..?
Maybe, I guess whatever they were intended for wouldn't be as crammed as an adaptor board & wouldn't need traces running underneath.
David
If you could pick between the Tek TDS320 and the HP 54602B which would you go for and why? I've been lusting over a digitising CRT scope for a while....
I am curious of others members input aswell, I seem to always be tossing between of buying a cheap new scope for a few $$ ( Hantek 2C10, $199) or go for one of these well known CRT scopes. ( usually around the same price.)
I just missed a Agilent 54622D, with some minor issues. It went for best offer(Damm!)
Another variant I am curious of the TDS410, seems very similar to TDS310.