1980's Bodge Porn!! Bytek S128 Gang Programer any Z80 Fans?  - Page 1
Forum section: electronics / general

author: KG7AMV
author_rank: Frequent Contributor
timestamp: August 15, 2021, 08:19:16 am
content: Had a old Bytek S125 Gang Programmer floating around the shop for a couple decades lost the program diskettes.Before I send it to the Recycler.. Decided to take it apart..Full Bytek S125 Gang Programmer TeardownYouTube:https://youtu.be/uIKHyYDF3MM

author: EEVblog
author_rank: Unknown
timestamp: August 15, 2021, 11:02:57 am
content: PCB re-spins are overrated!

author: bd139
author_rank: Super Contributor
timestamp: August 15, 2021, 12:47:18 pm
content: Wow that’s a crapfest and a half.

author: KG7AMV
author_rank: Frequent Contributor
timestamp: August 16, 2021, 06:29:57 pm
content: Quote from: bd139 on August 15, 2021, 12:47:18 pmJust think they charged about $1,500 for this back in the late 80's

author: bd139
author_rank: Super Contributor
timestamp: August 16, 2021, 07:22:44 pm
content: Yeah that doesn't surprise me. $100 of that was someone sitting there fixing it

author: rsjsouza
author_rank: Super Contributor
timestamp: August 16, 2021, 07:42:24 pm
content: Oh, c'mon guys... It was Rev 1.0!What a spaghetti board!

author: dl6lr
author_rank: Frequent Contributor
timestamp: August 16, 2021, 07:55:49 pm
content: Quote from: EEVblog on August 15, 2021, 11:02:57 amBack in the days we used IBM PS/2, I never saw a board without rework. The software was the same: Lots of Floppies labeled as PTF (Program Temporary Fix) or CD (corrective disk).

author: KG7AMV
author_rank: Frequent Contributor
timestamp: August 17, 2021, 12:21:22 am
content: rsjsouza the the Bytek S128 is on its way to you.. glad it will go someplace other the the e-waste facility.

author: srb1954
author_rank: Super Contributor
timestamp: August 17, 2021, 07:49:25 am
content: Quote from: KG7AMV on August 15, 2021, 08:19:16 amOne firm I worked for was so cheap that they even sold our development prototypes to the customer but we never let a board go out the door with that many bodges on it!

author: bobbydazzler
author_rank: Regular Contributor
timestamp: August 17, 2021, 11:00:55 am
content: I don't understand why they screw all the heatsink tabs down instead of soldering them?Maybe all the bodge wires were to add functionality cheaply instead of fixing layout problems?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 17, 2021, 11:11:43 am
content: Quote from: bobbydazzler on August 17, 2021, 11:00:55 amThey didn't have Metcal irons back then

author: Gyro
author_rank: Super Contributor
timestamp: August 17, 2021, 11:25:16 am
content: That's board's from the era of relatively low volume hand assembly and soldering (no solder resist for wave soldering), and through hole on both sides. Remember that it's also from (very) pre-smt times. It wouldn't have occurred to them to think of soldering the tabs, TO220s had a screw hole, so that's what you did.I can't remember when I saw my first soldered TO220 tab, but I probably saw it on smd power parts first.Edit: Come to think, I'm not sure that TO220 part datasheets back then would have had a tab soldering temperature spec, just the standard lead temperature of xxx'C for 10 seconds (still the case as far as I can see). It would have been quite counter-intuitive to heat the tab beyond it's maximum junction temperature spec. A bodge in fact.

author: tooki
author_rank: Super Contributor
timestamp: August 17, 2021, 12:10:35 pm
content: Quote from: Gyro on August 17, 2021, 11:25:16 amAbsolutely untrue. This programmer is from 1986-87 based on the last date code I could find in the pictures. SMT has been around since the 1960s, by the late 70s was already showing up in consumer electronics (for example, calculators), and by 1986 was found in lots of consumer electronics, like the Sony Handycam.And by that time, wave soldering had been around for decades (first done in the late 50s), and solder mask for at least one decade.

author: bd139
author_rank: Super Contributor
timestamp: August 17, 2021, 02:56:00 pm
content: Agreed. Either it was a prototype that shipped or it was a shit show of a company stuck in the bad days of the 70s.My father had a two man outfit that produced computer addons in the very early 80s and his stuff was all solder masked and wave soldered. The prototypes were wire wrapped on RS dev boards and the production stuff hand laid out on acetate by his colleague.

author: Gyro
author_rank: Super Contributor
timestamp: August 17, 2021, 04:42:46 pm
content: Quote from: tooki on August 17, 2021, 12:10:35 pmHey I didn't go and look up the programmer date, but it has a pretty similar look to an old ProLog one that we had at one company. That would have been beginning of the '80s, and would have been manufactured in the late '70s (we were programming 2708s). I'm not denying that smt wasn't being used in high volume stuff either, but for that sort of low volume product and smallish company, it would have been a pretty alien concept. - I still remember our first pick and place machine arriving when I was doing medium sized industrial stuff and that was in the early '90s. A few years before that though, when I was working for DEC, we were using double sided SMT (ok only passives on side 2, and bottom wave soldered) in our factory in Ireland.The sort of company that developed that board, for whatever reason, hadn't designed it for even flow (wave) soldering though. Regardless of the absence of solder mask, you wouldn't stick a bunch of regulators, connectors and even an EPROM on the back! It might have been an early board, but it was obviously sold as a finished product, so I don't think there's reason to write it off as a prototype either.You need to remember that there was a wide span of technologies and techniques in use across the industry in general. When you take into account sector and volume, there was a huge spread (having experience quite a lot of them).Yes, back in the early '80s we had pcb layouts were done with acetate and black crepe tape and that one was a fair sized company. Nice curvy tracks.Anyway, show me a TO220 datasheet from that era (or more recently) that tells you a tab soldering temperature and duration!

author: rsjsouza
author_rank: Super Contributor
timestamp: August 18, 2021, 02:44:51 am
content: Quote from: KG7AMV on August 17, 2021, 12:21:22 amSteven, u da man. Thank you very much for shipping it.Quote from: bobbydazzler on August 17, 2021, 11:00:55 amIt is rather unusual to see through hole TO220's tab soldered onto the PCB. If I saw one of these, I would seriously doubt their reputation to skimp on a decent heatsink with the proper mounting (not to mention my urge to say unspeakable words in case I was doing the repair on such equipment).Quote from: Gyro on August 17, 2021, 04:42:46 pmIndeed. Although SMT assembly was already common in consumer and advanced electronics in the 80s, it was mostly for the very large companies that could afford the production lines and not for a niche product like this - Contract Manufacturing was still in its infancy. Wave soldering and photolitography was indeed common, but so was hand taping, wirewrapping and hand assembly. I lost count of how many equipment from that era (including those fancy Hi-Lo or BP Microsystems programmers, Nohau emulators and others) that were fully through hole.

author: tooki
author_rank: Super Contributor
timestamp: August 18, 2021, 04:31:04 pm
content: Quote from: Gyro on August 17, 2021, 04:42:46 pmI never claimed otherwise. I was just saying that to describe that era as “very pre-SMT” is categorically untrue. It had already begun finding its way into consumer products by then, so it’s not as though it was bleeding-edge aerospace technology any more (as it was in the 60s).

author: Gyro
author_rank: Super Contributor
timestamp: August 18, 2021, 06:58:20 pm
content: Fair enough. I think the key differentiator in all this is 'volume'.

author: EEVblog
author_rank: Unknown
timestamp: August 19, 2021, 02:52:48 am
content: Quote from: tooki on August 18, 2021, 04:31:04 pmThe thing with bodges like this is the cost of crapping. Babe boards are one thing, but if you have added value by populating large numbers of boards then it becomes way more economical and senisble to bodge them.Happened with my 121GW meter, we found the PCB was the wrong thickness and that impacted the tolerance of the range switch, so some people had issues with it. We still had a crap load of fully populated boards so the crap them was not an option, so they went out with a shim to fix the issue for that run of boards.

author: bd139
author_rank: Super Contributor
timestamp: August 19, 2021, 08:01:15 am
content: As always depends on the customer.Many years ago we had a subcontracted out test fixture (bed of nails thing) which packed in after a month for the third time. Rather than send it back we looked at it and fixed it. Similar story inside. Mostly working but fixed with Kynar puke. The bending of the board eventually caused one of the wires to snap and then the tests failed. We got them to respin it at their cost while we pretended to hold the production line up for three weeks.The whole thing was a eurocard board with a DB50 on it and some regulators that bolted inside a frame. As we had in house PCB fab one of the design engineers sat and redesigned it and got a board spun and hand soldered the rest in about 3 days end to end. And we were back up.I was the unfortunate moron who spent an entire day trying to work out why my test suite was failing while assuming that the test fixture worked. Learned a lot that day

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 19, 2021, 09:25:12 am
content: Also, with something like a programmer, it could well have been the case that a new device came out, and the bodges were needed to support it.Even that amount of bodging would have been way cheaper (and quicker) than scrapping populated boards.

author: rsjsouza
author_rank: Super Contributor
timestamp: September 05, 2021, 07:39:41 pm
content: Steven, thanks again for sending the equipment. I released an overview video (sorry, only in Portuguese) but noticed quite a few interesting bits that reveal that either the Rev 1.0 sticker isveryreal or the PCB designer was quite inexperienced.- Several bodge wires were point-to-point GND connections to various parts of the circuit- Heaps of electrolytic capacitors were bodged to filter the power supply nets- Absence of 100nF decoupling capacitors in several high frequency parts, with quite a few bodged in place to fulfill this role - even on the main Z8400 µP and the DRAMs.- Very thin power supply traces throughout the PCB, quite contrasting with the beefy power supply- The PCB itself is very thin and quite unsupported with screws around the ZIF sockets - the designer relied on the PCB to be supported by a cutout of the metal housing, but it is slightly bent and the board then was left to fend for itself (it is a bit budged inside the box)- Very small clearances between the mechanical support (screw) vias and the surrounding circuitry - a misplaced solder and PUFF!Just like you, I could not find a software for it, but I found some discussions that mentioned simple serial port would be enough to communicate with the board. I didn't power it on, though (too many tantalum caps that may or may not be ready for a violent ejection).At any rate, follows the video below. Thank you again!

author: KG7AMV
author_rank: Frequent Contributor
timestamp: September 07, 2021, 06:01:50 pm
content: Thanks for the update.