EEVblog #918 - REPAIR: Sony Pyxis GPS - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: August 31, 2016, 11:31:56 pm
content: Dave fixes an LCD fault in a 1991 vintage Sony Pyxis IPS-360 GPS receiver.Could there be other issues though?

author: dragondgold
author_rank: Newbie
timestamp: September 01, 2016, 03:24:47 am
content: I have a doubt, why are there big fat tracks going to and from the 7660 charge bump if just before getting into the package pin the track width decreases significantly??

author: Chipguy
author_rank: Unknown
timestamp: September 01, 2016, 05:14:30 am
content: This charge pump is the Seiko Epson SCI7660C0B that has indeed a different pinout to the commonly known ICL7660.I found it here:http://www.datasheets360.com/pdf/-3789964963254906558Numbering that thing with 7660 is evil marketing

author: McBryce
author_rank: Super Contributor
timestamp: September 01, 2016, 06:58:09 am
content: A "Xilinx Z80" Dave?The Zilog fanboys won't be happyMcBryce.

author: LazyJack
author_rank: Frequent Contributor
timestamp: September 01, 2016, 07:39:55 am
content: Nice fix! (no pun intended).Initialization usually requires entering the approximate time and location of the receiver. This can speed up getting a fix, as the receiver will have some general idea of which satellites to look for. However, given that this receiver was powered off for who knows how long, you will need to wait until it gets the almanac and all ephemeris data from the satellites. This can indeed take half an hour or more. Modern GPSes have these data precomputed for a long timespan or just get it from the net, this is how the have very short time to fix.So just leave this outside (ideally far from high buildings) for a couple of hours, you will have a fix eventually. Unless this unit's firmware have problem with week rollower, which last happened in 1999.

author: EEVblog
author_rank: Unknown
timestamp: September 01, 2016, 09:32:11 am
content: Quote from: Chipguy on September 01, 2016, 05:14:30 amDamn, nice find.

author: madires
author_rank: Super Contributor
timestamp: September 01, 2016, 09:33:43 am
content: BTW, pyxis is the Latin word for can.

author: john72
author_rank: Newbie
timestamp: September 01, 2016, 10:32:15 am
content: Hi I'm John and new to the forum although I have been reading the forum for some time before joining.I first got watching your videos over a year ago now and fairly sure I've seen them all going back to the first one and really enjoy them. Thankyou for all the hard work you put into them for they cannot be easy to put together.Although I enjoy them all, I especially find the repair videos fascinating, probably because that's what I enjoy doing as a hobby. I especially get great satisfaction out of saving something from the landfill and giving it new lease of life.I've always had an interest in electronics and mechanical stuff since a kid and have over the last year re took up the hobby after I noticed that my TV and free view recorder and other equipment were falling not long out of warranty! (no surprise there)I thought I'd take them apart and have a look and have fixed them by changing the caps in them. Sometimes I find a different failure and it's sorted diodes.I watched your mailbag segment and noticed the hp psu and thought it might be intresting to take a closer look at that too, maybe see why it's failed and if it's repairable or not. (My guess at the start of this video was it might be bad caps.)Anyway think I'll leave my first post on that note, wish you good luck with the blog and look forward to waiting for your next videos.John.

author: jaromir
author_rank: Unknown
timestamp: September 01, 2016, 10:36:52 am
content: I noticed the SCI7660 voltage inverter has roughly one order of magnitude lower current consumption (cca 20uA versus cca 200uA) at no load. That may be important in battery powered device enough to choose over "industrial standard" ICL7660.By the way, I somehow remember one of the applications the 7660 was developed for was generating negative substrate voltage for older NMOS devices, like 8080. Is the 7660 really that old design?

author: Chipguy
author_rank: Unknown
timestamp: September 01, 2016, 12:52:08 pm
content: Quote from: jaromir on September 01, 2016, 10:36:52 amFirst mentioned in the 1981 Intersil databook on page 5-161 as "Preliminary"https://archive.org/details/bitsavers_intersildaDataBook_92107455

author: max_torque
author_rank: Super Contributor
timestamp: September 01, 2016, 07:29:31 pm
content: Whilst the other electrolytic/alluminium caps in the units are obviously old, they are quite possibly still all ok because they are just used for local de-coupling, and hence probably aren't working too hard, unlike the switching caps in the neg supply that must have a high current ripple and hence will run much hotter and have a significantly shorter lifetime. This is why we check supply voltages first, because components in these systems work hard and hence fail first

author: firewalker
author_rank: Super Contributor
timestamp: September 01, 2016, 08:06:46 pm
content: I would replace only the caps on the -5 rail.Alexander.

author: Tim T
author_rank: Contributor
timestamp: September 02, 2016, 01:19:39 am
content: Those electrolytics are apparently a common problem with some Sony products of that era. Google "Sony SW1 capacitor repair" where bad caps will result in speaker "motorboating". I recently did one of these repairs - not easy but do-able. The radio now sits on my workbench.tim

author: kripton2035
author_rank: Super Contributor
timestamp: September 03, 2016, 06:51:55 am
content: I would check the caps in the receiver unit ( and the gps unit) with an esr meter firstsure the 2 caps you swapped are esr faultyyou can check this without desoldering. ( remember you have a dick schmidt esr meter ?)

author: SeanB
author_rank: Super Contributor
timestamp: September 05, 2016, 06:27:51 pm
content: If it is Sony from the 1980's or 1990's, and there are those small aluminium can Sony made ( no manufacturers marking on them, but Sony always dogfooded unless not practicable, then always use another Japanese manufacturer for the parts they could not make), with voltages under 25V, do not even bother testing them, simply do a blanket remove and replace on them if you want to have the equipment work again.Sony had a few "service kits" for the electronic consumer and professional AV equipment that they made which were comprised of a pinch roller, a belt or two, a rubber idler tyre ( not the whole idler, just the rubber tyre), a plastic oil slinger for the capstan shaft, a small circlip for said shaft, a call for oil for said shaft and other points ( using a special Sony Branded Oil in a small Sony Branded bottle), a small set of instruction sheets, and then 200 SMD capacitors to replace all on the assorted boards. These would be supplied to the Authorised Agents and Repair Centres for in warranty repairs, and there would be a 20 hour or so labour charge for installing all those capacitors.If your kit made it out of warranty then that kit was really expensive to have installed, but for the Pro market they had either the choice of fit the kit, and have the unit running like it was brand new again, or scrap it and buy another new one if still in production. I have had a few of those bills over the years.