So You Want To Repair Audio gear, Eh? Here's the tools you need...

Discussion in 'DIY' started by EchoWars, Nov 16, 2010.

  1. r_brumett61

    r_brumett61 Active Member

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    295
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    Ct
    Yes the "JIS" (Japanese Industrial Standard) screw drivers are a must have for working on the Japanese gear. They look like phillips but are very different. I have bought them from "Stanley Tool" online.
     
  2. r_brumett61

    r_brumett61 Active Member

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    Ct
  3. jessbob

    jessbob Active Member

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    Location:
    waterville ny
    Fluke 73 iii multi meter

    Hi guys I finally have a dmm and it was free my boss gave it to me. I hope it will be a good one for tinkering with my audio stuff. Any input on this meter would be great. Bob.
     

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  4. EchoWars

    EchoWars Hiding in Honduras

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    It'll do. Nicely.
     
  5. jessbob

    jessbob Active Member

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    Location:
    waterville ny
    Thank you.
     
  6. Bigkahuna

    Bigkahuna Well-Known Member

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    848
    Location:
    Southern Maine
    I have been dabbling and have been able to fix a number of things. I have a couple of low wattage receivers that I plan to resurrect just for practice and to learn some things. I am very close to tracking down the last problem with my Nikko NR 1219 in the FM lock/muting circuit.

    I have a pretty good DMM just bought the Hakko soldering station and some other solder accessories. My soldering skills are pretty decent.

    I have one of those really inexpensive transistor testers coming. This also does capacitance and a bunch of other stuff. Looks like real cheap Chinese stuff but may help to confirm a bad component.

    I have just acquired a frequency generator that is soon to arrive, (pic attached).

    I have a couple of options for scopes that are fairly local to me.

    Tektronix 465 & DM43/DM40 Digital Multimeter on a cart w manual covers and probes $135

    Tektronix 2236 Not sure if it has probes. $100

    These seem to be my best two options. Which one would you choose?

    Also, I am wondering if there is a cheap solution to an RF generator for tuner work?
     

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    Willy6 likes this.
  7. soundmotor

    soundmotor super modified Subscriber

    Most gear I fool with is vacuum tube based so there are a tools I use more than any other -

    Bent needle nose pliers (angle lets you get around/under other components)

    Diagonal end cutters (look like needle nose but have cutter right at end, lets you cut lead up close after soldering)

    Desoldering pencil tool (slot on one end, point on the other, lets you unwrap soldered lead more easily)

    Solder sucker (clean out often when working)

    Ground lead for meter (banana one end, alligator other end)
     
  8. BOUXY

    BOUXY Super Member

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    Knowledge PERIOD!
     
  9. sKiZo

    sKiZo Hates received: 8641 Subscriber

    Is that a monthly thing? Will Midol help?
    Not today, Sansui ... I have a headache ... <G>
     
  10. BOUXY

    BOUXY Super Member

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    4,491
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    WPG,MB CANADA
    Not really it usually goes with Common Sense and realizing your limits!
     
  11. sKiZo

    sKiZo Hates received: 8641 Subscriber

    Oh, well then ... count me out ... <G>

    One thing that got me to where I am now is pushing the limits. That's how we burn ... er ... learn! <G>

    Oh. And I prefer uncommon cents ... they're worth a lot more ...

    [​IMG]
     
  12. camerakid

    camerakid Active Member

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    Location:
    California
    What 'scope would you guys recommend? It seems like every single scope I look at on eBay always has a description of something similar to "Unit powers on, we haven't tested it" or even "we turned on the oscilloscope, seems to be working" and one scope that I looked had "Powers on!" for the description. I found a TEKTRONIX 2215A on eBay for $150, Free Shipping, and the description is "This unit has been tested to power on and to ensure key functionality. The unit was able to successfully accept and display a signal during our testing. The unit may need to be calibrated prior to being put into full service. The unit is in good cosmetic condition overall with minor wear from previous use." would it be a good deal? But anyways, any links to scopes on eBay for the newbies like me are highly appreciated :)
     
    Last edited: Feb 9, 2016
  13. sKiZo

    sKiZo Hates received: 8641 Subscriber

    That's the main thing about used scopes ... most will need to be calibrated for professional work. However ... most will be fine for us amateurs to f'up around with in the basement workshop. Nice to see a pic of the scope showing a clear, defined, and steady trace if nothing else, just to confirm that the IO and tube are good.

    The 2215a is also a pretty fast scope for it's day, and should be plenty for "classic" audio. I've got a 2205 which is MUCH slower, yet still does what I want it to do.

    One thing to check for is if it includes the original probes. Those can be kind of expensive, but are a lot more accurate and reliable than the cheepo Chinese replacements.
     
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  14. JURB

    JURB Super Member

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    3,331
    Location:
    NE Ohio
    You can calibrate a scope with a DC voltmeter if you can make good enough square waves. I digital meter that can measure one volt with two digits after the decimal point has so much more resolution that it just doesn't matter anymore. You have to match the amplitude to the DC reference. With some generators it can be a bit tricky, plus the fact that you cannot count on it for the high frequency alignment of the scope. For that you should have an accurate detector probe to be able to measure a sine wave, even if it is not true RMS, you'll be comparing that to the trace on the scope so the meter is more accurate enough so that you can get it close enough for audio work.

    Aligning a scope is like aligning the IF strip of an FM or TV set. You are already supposed to know the intended results and be able to read it from the response you measure. All the instructions do really is to point to where the controls are, and if you are clueless, then where to start.

    But you really shouldn't be clueless if you are trying to align a scope. And let me tellya, when you get to those higher frequencies it turns into a real pain in the (_|_). you gotta use the friggin 50 ohm connectors n shit, ugh. And then, I was having a go at this (results were not all that bad though...) and found that someone had put friggin 75 ohm cable on BNC connectors ! I had more standing waves than waves ! OK, that is an exagerration but it made a mess. As a result I still don't have the high end of that scope aligned. It is good for general work but is supposed to be a 275 MHz. I can assure you it is not. Last guy tried a retrofit for an unobtainium vertical output IC and failed. He tried to realign the whole thing for that and pretty much rolled it. I tried a better retrofit, but then since we had another 1725a come in I decided to just install the correct part. It is close enough for now, later I'll get the detector probe and a few other things and hammer the rest of it out. Man this guy screwed with EVERYTHING. I know what he was doing, trying to get more gain. That was the problem with my retrofit, though mine was a hell of alot better. Got it from a site in Russia or something.

    Good old analog scopes are the best thing going. I have had them connected to my stereo at times, and know other who like to do that as well. A scope is literally an eyeball. It is like a meter may hear, but the scope sees.

    Anyway, as people have said not to tamper with like FM alignment unless you know what you're doing, this is the same but in spades.
     
  15. Wirehead

    Wirehead Active Member

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    235
    Location:
    Belgium
    One other option for a scope is the Rigol DS1000Z series. The base model (1054Z 50Mhz/4channel/1GS) can be unlocked to 100Mhz. (same hardware). Good scope for the money . They go for 399 new. But then again, totally not needed for most repairs :)
     
  16. H/K crazy

    H/K crazy Active Member

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    For audio work, you only need a dual trace oscilloscope and it doesn't need to be over 10-15Mhz. But in my opinion, if you are going to invest in a scope, you might as well pick up at least a 100Mhz unit since you may want to use it for other projects other than audio. It all comes down to price and manufacturer. I would stick to Tektronix and Philips scopes from the 1970's and 80's . I would avoid more recent scopes that have specialized chips and surface mount components. Why?, because the older thru hole technology scopes are more easy to repair due to their discrete components and the availability of more commonly found parts. These days you can still find 4xx and 22xx series Tek scopes in very good condition for very reasonable prices. 32XX series Philips scopes can be found for around $100 on the surplus market. I find them to be very stable and they have a nice crisp trace.
     
  17. H/K crazy

    H/K crazy Active Member

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    For audio work, I would suggest Wavetek models 142, 180, and 182, the reason being is that they go lower than 1 Hz and are great for speaker refoaming work. They do not take up the whole workbench and work well and are easy to service. The can be found on Ebay. H/P also good, but depending on the model, size can also become an issue.
     
  18. evoroadster

    evoroadster AK Subscriber Subscriber

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    Location:
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    Keep looking, there are some good deals out there. I picked up a Tektronix 2205-40 scope that was refurbished, calibrated and shipped free for $199 from Excalibur Engineering in Irvine Calif. It also came with a 1 year warranty.
     
  19. RossW

    RossW AK Subscriber Subscriber

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    I would add a set of mini vacuum attachments. I recently picked up a set of these:
    http://www.amazon.com/Micro-Vacuum-...&redirect=true&ref_=oh_aui_detailpage_o03_s00
    and they have made cleaning equipment so much easier.

    One the matter of scopes I will throw in my 2 cents and say you should really go for 100MHz+. They tend to be newer and/or higher quality scopes and if you ever intend to do RF work you will need the bandwidth. They're also not that expensive, a 465 is around $150 and is a hell of a scope.

    When looking at scopes make sure you know if probes are included. Good probes are not cheap. If you have the choice between a $100 scope with no probes and an $150 scope with probes, buy the $150 one.

    I saw a question on cheap RF generators, a cheap RF generator will not be good and a good RF generator will not be cheap. If you want to get started aligning tuners the Sencore SG165 is a good place to start for ~$250 (make sure it comes with probes, they are NOT easy to find). It is not the last word in stability or distortion but it's ok and if you're dealing with old gear it is certainly good enough to noticeably improve the alignment. It also has a built in dummy load with meters which is actually the most useful part of the thing (I use that feature at least once a week). A "real" RF generator is something like an HP 8662a but those are huge and expensive (broken units are $500+, working are $1000+). But one in good repair is the last RF generator you will ever need.

    One last word on test equipment buying: look for calibration stickers/seals. I'd rather gamble on a piece of equipment with cal seals intact because it means that even if it is broken you can be reasonably sure that no one else has messed around with it since it was working well enough to be calibrated. They will also sometimes tell you what is broken (usually a red-bordered sticker).

    Speaking of calibration, call up local cal shops and see what they charge. You will be surprised how cheaply you can get some stuff calibrated (I have a quote for $83.60 to cal a Tektronix 465 scope and $157.20 for an HP 8903B audio analyzer). Even very complex equipment can often be field calibrated with a fairly basic set of equipment. If you have a calibrated scope, multimeter, and frequency counter you can field calibrate a shocking amount of equipment.
     
    Last edited: Apr 4, 2016
  20. Wirehead

    Wirehead Active Member

    Messages:
    235
    Location:
    Belgium
    RF generators like the Sencore are hard to find in Europe. Any ideas what to look for around here? Any DIY kits by any chance?
     

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