Search found 1255 matches

by Dean Huster
Fri Oct 10, 2014 8:50 pm
Forum: General Discussion
Topic: Schematic diagram for Tektronix probe, please ?
Replies: 11
Views: 3023

Re: Schematic diagram for Tektronix probe, please ?

You'll find that the center conductor of the P6105A is resistance wire of fairly low value. This is a modular probe and both the compensation box and the probe head snap off easily. Other than the replacement of the three main components (head, cable, comp. box), the probe is not repairable. Active ...
by Dean Huster
Thu Oct 09, 2014 7:17 am
Forum: Lost and Found
Topic: Audio Power Amplifier -- "Electronics" magazine (McGraw-Hill
Replies: 1
Views: 1620

Audio Power Amplifier -- "Electronics" magazine (McGraw-Hill

There was one of these "Engineer Design Idea" type of articles in an issue of Electronics magazine, a McGraw-Hill publication that was 90% advertizing, thick, clay-coated glossy paper, etc. A professional magazine for engineers. The magazine article appeared somewhere around 1971-1972 and the circui...
by Dean Huster
Wed Oct 08, 2014 6:10 pm
Forum: Nuts & Volts Magazine Discussions
Topic: October 2014: "1963 Zenith MK2670 Stereo Repair"
Replies: 0
Views: 3112

October 2014: "1963 Zenith MK2670 Stereo Repair"

NOTE 1: Mention is made of replacing paper-dielectric capacitors because leakage (electrical, not chemical) causes heat and heat makes them explode. No mention is made for the major reason to replace these nasty paper-dielectric caps: the same leakage that allows the passage of DC in coupling/block...
by Dean Huster
Sat Aug 23, 2014 12:00 am
Forum: General Discussion
Topic: Trying to find / download a service manual...
Replies: 6
Views: 1588

Re: Trying to find / download a service manual...

Yeah, there's two or more manual sites that want to download their "downloader" to your computer -- it's the only way you can download their manuals. And I'm sure their downloader program comes with all kinds of "helpful" toolbar add-ons and other browser surprises. I've yet to utilize one of those ...
by Dean Huster
Fri Aug 22, 2014 11:56 pm
Forum: General Discussion
Topic: Cure for failing remote controls...
Replies: 6
Views: 1491

Re: Cure for failing remote controls...

I've found that "oil" inside them also, and don't know what to make of it. I really can't believe that it comes as body oils -- my hands are always dry and calloused and I don't rub my forehead with the remote, which would flood the poor thing. I tend to clean the button surfaces and the PCB contact...
by Dean Huster
Sat Aug 09, 2014 7:53 pm
Forum: General Discussion
Topic: microcontroler circuit design question / new digital scope
Replies: 7
Views: 1504

Re: microcontroler circuit design question / new digital sco

Scope probes will transfer to another scope just fine. I'm not much for buying a new scope over a used one. For the same price, a good, used one will have better performance, usually be of better pedigree and be more robust. The Chinese import will have horridly-written instructions and little to no...
by Dean Huster
Wed Aug 06, 2014 6:32 am
Forum: General Discussion
Topic: Toshibe laptop = toaster oven
Replies: 19
Views: 3115

Re: Toshibe laptop = toaster oven

Of course, chips run hotter these days that they did in the day of the 8080A and 6800. Is the computer in peril of a meltdown or just it just seem that way to you? You may be trying to repair something that isn't broken. It drives me nuts when my wife uses the laptop with it laying on a pillow or so...
by Dean Huster
Wed Aug 06, 2014 6:28 am
Forum: General Discussion
Topic: Velleman kit
Replies: 5
Views: 1247

Re: Velleman kit

You're over-reacting, Len. Maybe half a zillion at most. Forgive me if it seems like I'm "preaching" to the choir, but I have to throw this out to you anyway, just to make sure you have the bases covered. Most pads lift because of solder temp that's too high or worse yet, too much time spend solderi...
by Dean Huster
Wed Aug 06, 2014 6:12 am
Forum: General Discussion
Topic: microcontroler circuit design question / new digital scope
Replies: 7
Views: 1504

Re: Tektronix 465 scope / micro input question

I'm here, too! One thought you need to consider regardless of what scope you use to try to capture the glitch is this: how will you trigger the scope (regardless of whether it's an analog or digital one) to catch the glitch? Does an output somewhere do something totally different when the glitch occ...
by Dean Huster
Wed Jul 30, 2014 5:31 am
Forum: General Discussion
Topic: Old Magazines
Replies: 2
Views: 2419

Re: Old Magazines

I sure get a lot of "error pages -- this page not scanned" when I try to look up an article in Electronics Illustrated.
by Dean Huster
Wed Jul 30, 2014 5:26 am
Forum: General Discussion
Topic: Toshibe laptop = toaster oven
Replies: 19
Views: 3115

Re: Toshibe laptop = toaster oven

The Toshiba I'm working from right now is just that -- a toaster oven. It get really warm to the fingers at the output of the fan's airflow. I've a feeling that it's part of the package!
by Dean Huster
Wed May 21, 2014 6:26 pm
Forum: General Discussion
Topic: TV signal conversion
Replies: 2
Views: 761

TV signal conversion

I have a Sony video/audio receiver that has always been wonderful. Enter HDMI. The only way (that I know of) to hook up my new Blu-Ray player is through a HDMI cable directly to the TV which bypasses the audio system and gives me crap for sound, quite the opposite of what you want with Blu-Ray. TV h...
by Dean Huster
Wed May 21, 2014 6:20 pm
Forum: General Discussion
Topic: Antenna Signal Meter
Replies: 11
Views: 1631

Re: Antenna Signal Meter

In the Navy, we used the Singer/Stoddard NM-25T. It was exactly as you describe in your wants, but limited to 30MHz or so as I recall. There were other models that went higher in frequency. We had to sweep the HF bands back in the 1970s to do site surveys to check background noise. It was a very bor...
by Dean Huster
Wed May 21, 2014 6:17 pm
Forum: General Discussion
Topic: Why won't my motor spin?
Replies: 17
Views: 2981

Re: Why won't my motor spin?

Tektronix used similar circuit for the fans in the "new" 400-series portables. The transistors were in a Motorola array that just happened to be in a symmetrical 14-pin DIP. If the motor was hung, you just unplugged the array and put it in the socket backwards. If the motor then started on power-up,...
by Dean Huster
Sat May 17, 2014 7:42 pm
Forum: General Discussion
Topic: batteries
Replies: 14
Views: 2051

Re: batteries

I have a pair of "antique" "D" cells. My old brain won't let me remember the brand name -- black and white stripes -- why can't I remember this? Anyway, this pair looks good as new. I don't think the brand has been around since the 1950s or early 1960s. Each measures about 0.5 to 1v, so there's some...