Tektronix 545 and Fluke 77 - Page 1
Forum section: electronics / beginners

author: SgtRock
author_rank: Unknown
timestamp: April 21, 2011, 04:02:22 am
content: Greetings EEVBees:A heartwarming story of two, slightly long in the tooth, fair lassies of the Great Northwest , one from Beverton and one from Everett, both with the same Papa.My next door neighbor was kind enough to give me a Tektronix 545 O'scope with manual, extra plugin, tubes & original manual. Bonus!! "Part it out for tubes", you say. Plainly Suh, you are a Yankee, and no gentleman. I plan to check all the tubes, resistors, caps etc. I will be using 3% silver solder on the ceramic bus trays. I will clean the filter, lube the fan and motor, and bring er up slowly & carefully with isolation and variac. I welcome your suggestions dear reader as I am truly out of my league.Ted (the neighbor) told me he had a Fluke 77 that was not working. I told him I would like to have a go at fixing it. With trepidation, he handed it over. It was a forlorn sight with missing screws, a scratched window, and no discernible display, but it was a Fluke, Sigh!!With a lump in my throat, I took of the top shell and removed the LCD plastic clip (which I broke, oh well 10 bucks Epay), I discovered if you press down hard enough it indeed had a readout, but appeared to be stuck in the turn-on mode with all display elements lit up, as best I could tell, pressing down hard with both thumbs and praying not to break the LCD glass. The crappy readout was familiar to me from working on Fluke 87s. It was going to need careful cleaning of the pcb traces, and the (nearly invisible) traces on the back of the LCD glass, and new elastomeric connectors for the 77 I.E,. Fluke Part # 69632.I found almost the correct service manual on the Web. I then tried unsoldering and testing the cheap easy to obtain parts, to no avail. The manual told me (in the troubleshooting chart) to check a voltage at test point 3. There was none. The the U1 IC chip Fluke 75-4502 (Fluke Part # 649632) would need replacement.I floundered around a week or two on the Web, fighting my way past data sheet pirates and Hong Kong outfits with $200 minimums, trying to find said parts. I finally gave up and called Fluke in Everett WA. Fluke said no problem if you do not mind waiting a month or more and paying $20 US plus shipping to be determined. The nice lady from Fluke added that the IC chip had beensuperseded by a new one which would work like the old one. I placed the order.Five weeks and $27.01 later I received my two elastomers and the IC chip, which was NOS and was the original number after all. I installed the rubber and put the new LCD clip on and bingo I had a perfectly working display, albeit, stuck in the turn-on mode.I then proceeded to desolder the IC chip using Chip-Quick. Great product! With fading eyesight and trembling hand I was able to solder and wick and test and resolder and rewick the SMD 60 pin dime-sized chip. I replaced the missing screws, and Bob's your nuncle, it woiks. Belatedly I noticed I had no peeper. I had to clean the brass on the peeper, carefully reposition the little conductiverubber dots (slightly larger than the period in this sentence), and make sure the solder contact points on the pcb were tall pointed and tits up. I cannot wait to give it back to Ted as soon as I finish polishing the scratches out of the window with Novus 1,2&3 plastic polish.While checking the accuracy of Ted's freshly repaired Fluke 77, to my chagrin I discovered that one of my 87s (one from Ebay that was guaranteed freshly calibrated), was not only out of calibration but both HRC fuses were blown. It read fine on everything but amps. I would have never known if I had not been checking the milliamp setting on the Flukes. I found the replacement fusescheapest at Amazon. The good news is that Ted's 77 was fine. I am beginning to get an inkling of what Dave said about "burden voltage" and am developing a hankering for a uCurrent.Ted was telling me he has an aunt in Australia. So I told him the story about all the prisoners being shipped to Botany Bay, and how on the way over, all the vowels fell overboard except for the ones rhyming with might. Chuckling politely, Ted then told me the one about the WWII Yank pilot who was shot down and woke up on an Australian hospital ship. Fearing the worst the wounded pilot asked the nurse "Did they bring me here to die" She answered "Wuh no Suh, they brought ya ere yestadye"No offense intended DJ.You EEVBees, do not forget to click on Dave's sponsors and buy from them when you can. Dave is the soul (sic, stet, stat) means of support for a large family of multimeters.In the immortal words of Engineer E.E. Doc Smith, Clear Either.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 21, 2011, 06:02:19 am
content: well, interrupt 0xH08:1) i'm not native englishman2) i hate few cm's thick love story book3) i love pictures!cheers

author: slburris
author_rank: Frequent Contributor
timestamp: April 21, 2011, 05:36:33 pm
content: Quote from: SgtRock on April 21, 2011, 04:02:22 amFor help with the Tek scope, I highly suggest joining the Tekscopes and Tekscopes2 groups over at Yahoo groups.http://tech.groups.yahoo.com/group/TekScopes/http://tech.groups.yahoo.com/group/TekScopes2/Why 2 groups? Well, legend has it that the moderator of tekscopes banned somepeople for OT posts, so they fled to Tekscopes2There are also some Fluke meter guys hanging out here:http://tech.groups.yahoo.com/group/Fluke_DMM/Scott

author: Excavatoree
author_rank: Frequent Contributor
timestamp: April 22, 2011, 09:25:57 pm
content: Hello and welcome!I'm a big fan of the Fluke 70 series, and I'm glad you saved another one from the scrap bin. I've never been so ambitious as to change that IC - I've had to re-solder a few, however. It seems Fluke had a bad batch of assembled boards where that chip didn't get soldered very well.As for the old Tek scope, well, I've tried my hand at those, and not had much luck. If you need any parts, let me know - I've got a few. Mycapacitorss are probably worse then yours, however, but I've got some other serviceable items.I guess I need to post a picture of the "scope shelf" to go with the staircase meter photo.

author: Rick
author_rank: Frequent Contributor
timestamp: November 09, 2012, 04:26:57 pm
content: Quote from: SgtRock on April 21, 2011, 04:02:22 amNovus 1,2&3 plastic polish... I think this is what I need to polish the lens of my Fluke 27's. The local distributor does not have the spare parts for this multimeter. Thank you.