Pros and Cons of Keysight publishing service info when products are obsoleted - Page 1
Forum section: electronics / testgear

author: TimInCanada
author_rank: Regular Contributor
timestamp: April 09, 2017, 07:39:29 pm
content: Dave's recent video on a HP 54616B scope (https://www.eevblog.com/2017/03/27/eevblog-982-hp54616b-500mhz-oscilloscope-repair/) showed the trouble he had getting any service info. In the Keysight documents there is only the Component Level Information Package (CLIP) on the earlier 54600A model, which may or may not have complete schematics and has nothing on tests or signal specs. I'm cleaning up a 54610B that has a couple issues I'd like to address, but the Operating and Service Manual only provides detail to the level of "if X, replace the power supply, else if Y, replace the system board".That approach makes economic sense when the instrument is currently supported by the manufacturer, is valuable enough to justify the cost of replacing major subassemblies and would cost the owner if it was removed from service for long to diagnose and fix component-level problems. The manufacturer can even encourage the purchase of new equipment by progressively raising the prices of the replacement subassemblies until it's cheaper to buy new than service old equipment. So you can understand the business model.The trouble is when the equipment gets old and cheap enough for hobbyists who can spend the time to find and fix individual components. Instructions like "replace the system board" aren't that helpful (especially since Keysight no longer sells the boards, even if the price was justifiable). As Dave's video mentioned, all those chips with HP 1820-xxxx part numbers defy replacement, even if you can determine one is bad.Contrast this to a generation before. I'll use the example of the HP 3325A Synthesizer-Function Generator (as I'm deep into one now). The Operating and Service Manual dated 1984 is available on the Keysight website. It has a Replaceable Parts chapter which, for instance, tells you a 1820-1196 is really a SN74LS174N. There is a chapter on Theory of Operation. The Service chapters describe individual tests to perform and what the results should be. This manual even describes which components were most likely to fail. These old manuals were glorious. A person can learn an awful lot of electrical engineering just by reading them.So here's what I'm wondering: what would be the Pros and Cons for Keysight to put up real service information for the "newer" old HP equipment? Taking the 54600 scopes as an example, some items such as the keyboard pcb were just replaced with new if there was a problem. There would be no service procedures but there would be schematics, parts lists and perhaps some signal specifications. Other parts, such as power supplies and system boards, were replaced on an exchange basis. Presumably one or more HP facilities repaired units off-line and put them into service part inventory. Service instructions, presumably, would exist for these parts.When Keysight declares a product "Discontinued" they still provide support. When they declare it "Obsolete" they stop providing support. What might it mean to Keysight to provide full service info for the obsolete products? Here are my guesses:PROS:Goodwill, mostly:- People with obsolete HP/Agilent/Keysight equipment won't be stuck if it breaks. These people probably won't be financially able to buy new Keysight replacements, so if the lack of service info forces them to junk an instrument, Keysight wouldn't benefit with a sale. Maybe such people would buy another used HP/Agilent/Keysight for a replacement, but I think more sales would go to Rigol, Signlent, et.al. Given Keysight just introduced the "cheap" 1000x scopes, attracting entry-level customers to their brand must be important for them. Why not make it easier for entry-level customers to own HP and Agilent equipment as well?- Add to "green" credentials. If it is practical to repair your HP 54600 scope, it's a lot less likely to end up as electronic waste. My HP 3325A is date coded 1980 and it's repairable. I don't consider it disposable. The HP 54610B? It won't take much of a failure for it to end up in electronic recycling.- Help educate potential customers. The old HP Journal was a great marketing tool. While it was almost all about promoting new products, I'll bet an awful lot of EEs gained technical knowledge from it, just as with the Theory of Operation chapters in manuals. Did these materials leave a positive impression of HP? They did with me.CONS:- Cost of collecting and posting service materials. Presumably everything would be already in electronic form and easily available so cost shouldn't be too high.- Makes it easier for competitors to reverse engineer products. If anyone reverse engineering 20+ year old products could be considered a competitor, that is.- Raising potential legal liability if known product defects had been covered up. Pretty unlikely, I would expect.This is all just wondering out loud. Maybe people in the industry with some knowledge of how such decisions are made can shed some more light.Tim

author: retrolefty
author_rank: Super Contributor
timestamp: April 09, 2017, 08:01:06 pm
content: Yes the service manuals of HP test gear up through the 80s at least were along with Tek scopes were the envy of the industry. Now I guess the industry is too competitive and cost concerns to offer such over and above product documentation. Well at least I have past memories to comfort me.

author: ebastler
author_rank: Super Contributor
timestamp: April 09, 2017, 08:27:20 pm
content: Well -- do they evencreatereal service manuals for the newer generation instruments?I would assume that the instructions for their in-house service team are largely along the lines of "if self-test says X, replace board Y", or "connect proprietay test jig; if it says A, replace module B". Not sure whether they still expect their service personnel to drill down to the level of schematics, test signals, and measuring at test points?If that's the case, then today's "service instructions" would be pretty useless for amateurs who do not have access to replacement boards or proprietary testers.EDIT: Upon re-reading the initial post, maybe that's implied there too, and TimInCanada is not suggesting that KeySight should publish already existing (but internal) manuals once an instrument goes obsolete, but should put together dedicated materials for do-it-yourself repairs?That would add a very significant CON argument: "Dig up 15-year-old development documentation, verify which version(s) of those documents actually describe the production instrument(s), put everything together in some meaningful way, add safety information and all kinds of disclaimers, etc.". I doubt they could justify the effort just for the goodwill of the amateur community (which is not even their main customer base).

author: KE5FX
author_rank: Super Contributor
timestamp: April 09, 2017, 08:48:49 pm
content: Quote from: TimInCanada on April 09, 2017, 07:39:29 pmNot only that, but the HPJ articles were frequently better at explaining how something worked than the manuals themselves were. The 8662A has a service training manualanda four-volume service set, but I never really grokked its architecture until I read the Feb '81 HPJ.QuoteThis has always been a frustrating argument. Someone who is going to copy your product is not going to be impeded in the slightest by the lack of a schematic in the service manual. Like most forms of "copy proection," withholding service information has no effect other than to punish paying customers.QuoteOne concern that's somewhat more legitimate is attracting patent trolls.

author: MadTux
author_rank: Frequent Contributor
timestamp: April 09, 2017, 08:54:48 pm
content: Also far too many hard to replace/unobtainable/unprogrammable parts inside new instruments.E.g. Touch screen LCD vs 7seg. LED, 74 logic vs a CPLD, old school uC with external ROM vs ARM with internal ROM and fusebit, rubber matrix vs classic HP buttons.... Also lots of BGA with multilayer PCBs now, SMD transistors that don't have clear markings...If one of these things mentioned above fails in a new instrument and you can't find a replacement, the instrument is usually done, whereas in the older instruments, replacement was rather simple, as generic parts were used. Guess repairing old instruments in 20years won't be as much fun as it is today. It's more like have fun while it works and junk it (sell it in parts) afterwards.

author: nctnico
author_rank: Super Contributor
timestamp: April 09, 2017, 09:13:15 pm
content: Don't be overly dramatic! Nowadays you can easely join forces with people online to fix equipment. There are many examples on this forum where people get complicated equipment fixed without schematics.

author: TimInCanada
author_rank: Regular Contributor
timestamp: April 10, 2017, 06:39:58 pm
content: Hi ebastler, no, you read it right the first time.What I was thinking about for effort to publish service information is that it may be spread across different company locations, in different formats, etc.It's very likely that most relevant information for each product is easily available, however. To sell in the EU the product needs a CE mark. For the CE mark the manufacturer needs to maintain a Technical File for each product that can be produced for inspection by EU authorities at any time. The file needs to be maintained for at least 10 years after the product is discontinued, and the manufacturer is free to keep it longer. The relevant materials the file must contain include at least:Description of the apparatus, usually accompanied by block diagramWiring and circuit diagramsGeneral Arrangement drawingDescription of control philosophy/logicDatasheets for critical sub-assembliesPart listCopy of instructions (user, maintenance, installation)Quality control & commissioning proceduresThere may be some proprietary information in such documents that wouldn't be helpful for service. If there is then there would be effort required to remove it before publishing the service information.I do suspect that repair procedure information is documented even for lower price instruments. For example, on the 54610B scope the user manual gives a trouble shooting procedure and in some cases the result is to replace the system board. HP offered two options: a new system board p/n 54610-66508 or an "exchange" system board p/n 54610-69508. An exchange board would be a used board that has been repaired.HP was repairing equipment so it would make sense for them to create service instructions for their technicians to use. The first time a particular problem is seen you would want a very skilled engineer/technician to diagnose it. If they document the solution then in the future less skilled (and less expensive) technicians could be used to fix that kind of problem. If there are repair facilities in different locations you would also want to share knowledge between them.Much HP equipement would have such low production volumes that building automated test equipment for repair work would not be justified. Probably there was automated testing for the higher production products. Even then, the automated tests done had to come from somewhere. The test machine has to be programmed with a series of "apply stimulus A, measure response B then do C based on the result" actions. Maybe the test specifications are documented other than in the test machine software?I agree that no manufacturer would create new service information for obsolete products. A lot of useful service information, I suspect, isn't too far away from the internet. And I guess I may be too sentimental at the thought that a piece of HP test equipment could die unnecessarily.Tim