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

Radiometer Electronics (often branded RE) made some decent RF stuff in Europe. I've actually been considering buying one of their FM Multiplex generators because they are relatively inexpensive (most people have never heard of them) and supposedly of high quality. The advantage of something like the Sencore is that it will do everything (10.7 MHz sweep/markers, AM and FM RF, Multiplex, etc.).
 
Yeah, there's some real updating I'd like to do here, but I can't because of the 10K character limit, which was imposed some time after the original post.
 
I would like to thank you for this great post. It keeps on giving. I am retiring soon and was looking for a hobby to fall back on that was doable from the comfort of ones home. Something that you could pause at any time.I currently have a need for HP but will soon be too old to pull transmissions or crawl under the dash. You D man! :)
 
1. Oscilloscope - Nope
2. Audio Signal Generator (10Hz~100KHz) - Does an app count?
3. Solder station or solder iron - Yup
4. Digital Multimeter(s) and minigrabber leads - Yup
5. Dummy Loads - Nope
6. Dim-Bulb tester - Yup
7. Digital Caliper - Nope.
8. Solder - Lots
9. Solder Paste - Nope
10. Solder Wick - Yup
11. Solder Sucker - Nope
12. 170 Side Cutters - Nope
13. Hand Drill & small bit assortment - Yup
14. Machinists Scribe - Nope
15. Bondhus Metric and Standard Ball-End Allen Wrench Set - Nope
16. Helping Hands - Nope
17. Assorted Hand Tools (#1 & #2 Philips, pliers, wire strippers, etc.) - Lots

am i ready to do amp reapirs?...
 
1. Oscilloscope - Nope
2. Audio Signal Generator (10Hz~100KHz) - Does an app count?
3. Solder station or solder iron - Yup
4. Digital Multimeter(s) and minigrabber leads - Yup
5. Dummy Loads - Nope
6. Dim-Bulb tester - Yup
7. Digital Caliper - Nope.
8. Solder - Lots
9. Solder Paste - Nope
10. Solder Wick - Yup
11. Solder Sucker - Nope
12. 170 Side Cutters - Nope
13. Hand Drill & small bit assortment - Yup
14. Machinists Scribe - Nope
15. Bondhus Metric and Standard Ball-End Allen Wrench Set - Nope
16. Helping Hands - Nope
17. Assorted Hand Tools (#1 & #2 Philips, pliers, wire strippers, etc.) - Lots

am i ready to do amp reapirs?...
While an oscilloscope is not needed per se, it does make some debugging / aligning easier. I use mine as a combined DMM/Scope (DC coupled). Gives me more info in regards to oscillations on a rail. An app as signal generator will suffice in the beginning. Be careful you don't blow your device up though! A small audio range oscillator is cheap and might be more flexible in the end. A dummy load might be needed for amps where there's an output meter that needs adjusting. I'd say definitely get a solder sucker. You get much lower "heat-to-part/board" times when using that instead of solder wick. Side cutters are a must imho. Doesn't need to be expensive stuff to start! Best tool is your brain! :)
 
A few additions I would make:

- A good light source, it's hard to troubleshoot and repair if you're squinting in dim light, a flashlight is also helpful
- Hemostats, easier than pliers for complex tasks because they're smaller and latch unto whatever you're holding
- Heatsink grease, I prefer non-silicone electrically insulating personally
- Heatshrink assortment, lower importance but still handy to have around, especially for point to point wiring in older gear
- Bleeder resistor for PS caps, 50kohm 5watt is a good general purpose resistor for SS and tube work up to 500V.


Haemostats are the unsung hero's of teche tools - go to a hospital and beg for old ones :)
 
Got some downtime while waiting for some parts, and since I had made this list for a friend after giving it all a lot of thought, I figured that I might share with you my findings...

In general, the focus here was to get the best bang for the buck. There are more expensive options, and less expensive options, but I wanted a good balance while keeping a close eye on the total expenditure.

The raw list consists of (and I will go into detail for each in the next section):
1. Oscilloscope

12. 170 Side Cutters

Let's look at these one by one:

1. Oscilloscope
I like to recommend the Tektronix 465B, as Tek sold more of these than pretty much any other scope in history. It is reliable, rugged, repairable, and easy to use, and can be bought in perfect working condition for under $500 ($200~$275 is not uncommon, even for a nice one). There are tons of spare parts around, and any scope repair guy knows this one, if he knows any at all. There are other options, but for someone who simply doesn't know where to start, you won't go wrong here.

12. 170 Side Cutters
Why 170? I dunno...they don't measure 170-anything in any dimension that I know of, but yet 170 cutters are an industry standard, and nearly every electronics tool maker has a version or two. Here's a version from Swanstrom Tools at Digikey (#232-1025-ND).

.BUT, if you have constructive criticism to add, or other options that I have not included, you are welcome, nay, encouraged to add your thoughts.

I use a TEKTRONIX 475B - absolutely the BEST scopes you can get

Side cutters are the main tool you can own get the best you can afford - Mine are Lindstrom !!!!! I would pay just about any price for a good set of cutters :)

Great thread by the way :)
 
the was a restoration, now it works :)

"I use a TEKTRONIX 475B - absolutely the BEST scopes you can get"

I don`t like messages like this. The best scope you can get is always that scope what do all you need, for the smallest money.
when it provides a very lot of features you never will use, they are not important to have.
Very important is to get a perfect result in the tests what are always on the table.

Some people work only in amplifiers, they are happy to use a slowly dual beam with a large screen and very sensitive inputs,
others like to repair tuners, they need a fast one with very low pF at the probe tips,
others want to put the scope in the car to go anywhere to use it for service ( portable scopes),


and - so - on.
There are so many different scopes in the market bec. there are so many different needs.

greetings
Martin (I am collecting scopes.)
 
Thank you for this great post. I'm considering trying to start learning some very very basics and am looking for a multimeter. Do you still recommend the Fluke 114 & 115 or has anything changed in the years since you made this post? Price is definitely a concern with all of this but I don't like to buy multiple times and waste money in the process. I'd rather buy as good as I can afford once and be able to count on it.

Edit: Is your recommendation for a soldering station also still the same? Thanks again in advance!
 
Yes, I still like the Fluke meters. If saving a couple of bucks is important, the Amprobe AM-510 or AM-530 are pretty good alternatives. The Triplett 9045 is also a pretty full-featured device. You still need minigrabber probes with whatever meter you choose: Digikey PN 501-1060-ND for 48" black, and 501-1061-ND for 48" red. Every meter you own should have a set of these.

Hakko replaced the 936 with the Fisher-Price-looking FX-888D. I still recommend them.
 
I was able to find a nice used Fluke 115 multimeter for a good price. Unfortunately it doesn't have the users manual. I am new to using DMM and work of this nature in general. If anyone has a manual for this DMM and wouldn't mind sending it my way I would gladly pay the shipping plus a couple bucks for your trouble.
 
Hi all,

Thanks for all the great info and discussion.

I bought a Seeedstudios DSO nano v3 handheld oscilloscope a while back to play around with. Would something like that work for repairing SS gear? Would it at least be useful for some types of tests? This thing has a function generator too, though I haven't messed with it yet. For about 50 bucks this thing could be a heck of a deal.

I'm just not familiar enough with o-scopes to know what features and specs I need to pay attention to. Also, if anyone knows of a good basic/ beginners guide for using an o-scope for audio repair, I'll do my own search but I'd like to know what the experts deem useful.
 
Looking at getting a proper function generator, but just wondering when bench testing would I need two of them to test both channels at once?

Thanks
 
Has anyone mentioned yet that a set of JIS screwdrivers or screwdriver bits is imperative for working on Japanese gear?

They look like Phillips or Pozidriv but are neither. Identified by a dot between two of the cross-slots on the head. Using the proper JIS driver greatly reduces the possibility of cam-out, and they even can help you bust loose Phillips screws, a JIS driver in a Phillips head screw works better than the proper driver, whereas a Phillips driver doesn't really work well on either.
 
Hi guys,

Now that old HP test equipment is on the auction market at very reasonable prices, I suggest a few that I have bought over the last few years. In most instances, since prices are so reasonable, I have spares units too because many of the specialized parts are obsolete.
Since they are old, expect to service them at some point in time, so manuals are important to have. All the service manuals are available, for many I have the original manuals.
I used to cal/fix these instruments in the 80's when I was a young tech working for Motorola Comm, so I am very familiar with them. The manuals are very well written and easy to follow.
The only thing I can see against these old instruments, is that many of them are big and heavy. Also since they are old, well what do you expect, you are probably are going to have to repair them at some point in time. If you are not up that task then buy something with a warranty or is much easier to repair.
I did not spend any more than $200 for each, except for the HP 8656B RF SG, iirc was around $350? I got it with a failed cal sticker, for no AM mod, it turned out to be the 10-bit DAC, MC3410, which I was lucky enough to have one in my spare stock.
You have to be carefull because the deals are for instruments that the sellers buy at auctions, but in many cases they do not know how to test them for op performance, thus the discount.
The only HP gear that I will not recommend is old analog scopes, I recall having to repair them more than Tek, for that I like Tek scopes, 22xx,24xx series, are fine, but do not own them, since I have newer digital scopes.
Most of the higher end gear uses the HP-IB remote control, thus they have extra features and enhanced performance, although I do not use the bus itself, since I use the instruments in manual mode all the time.
So here is my partial list that I use for fixing receivers.
HP 3325A synthesized function generator.
HP 3478A 5-1/2 digit DMM, it has excellent AC specs
HP 5316A freq counter, with 1GHz option, but 1G opt is not required for most use.
HP 8656B RF SG

happy testing
 
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