how to save money on experimenting with Electronics

Hello Everyone, As i don't have large amounts of money to spend on my electronic projects, one way i save money is to ask all my friends, relatives and family that when they are getting rid of their monitors, video recorders, printers, computers etc etc that instead of putting them with the rubbish to pass them on to me.

You would not believe the amount of heat sinks, large value greencaps, high wattage resistors, mount brackets, screws etc etc not forgetting the transformers of different voltages that come in useful to drive my smaller projects.

The best thing about using secondhand components in that when an experiment goes wrong and goes up in smoke, who cares as the components cost nothing.

Once i have the design right, i build my final project with new components, knowing that my project will work.
Many of us started that way. When I was a kid I used to go out behind the local TV repair shops and raid the trash bin. I would haul old TV chassis home and strip them for parts. CLose to 50 years later and I still have some of those old parts around here somewhere. Like the old resistors with body color and dot for resistance code. And I also gained an appreciatioin for parts as art. I always liked the design simplicity of the innards of a 1B3 HV rectifier tube. And the squatty little 6H6 metal octal dual diode. And I am still very much appreciative that we no longer use wax capacitors in anything. OOky mess, those were.

I appreciate surplus to this day. I am not far from Michigan State University - a college with about 45,000 students. Big place. MSU, like many universities, has a "salvage" facility. Nothing is discarded, any surplus gear is sent to salvage for liquidation. You can go in there and find all manner of stuff. Cheap test gear. Plenty of electronic things good only for parts. I once bought a large polygraph machine for $10. A five foot tall rack on high quality casters. The wheels alone were worth $50. Very nice equipment rack. The rack was full of amplifier modules and things. Many vrey high quality parts for next to nothing. SOmetimes they have things like ph meters from the bioilogy labs. Nice sloping panel box with a very large needle meter on it. Cost? a dollar or two.

In any case, it might pay to explore the local institution of higher learning to see if they have a disposal facility for obsolete gear. I bought a door there once too.
I started that way as well.

Also got lots of parts from things being thrown away at my old tech school. I got a really large transformer that can change 115V to 220 or 240V also has 190, 200, 210 volts on the secondary and 75 or 90 also on the primary. Completely free, and comes in handy for testing things at a lower voltage, like when you first test a new amp just built.

From various folks, got computer monitors (GREAT for HV small signal transistors) VCR's, TV's, etc. Also got some power transistors from a dead car amp.

Now along with my numerous used parts (always test with meter before using) I ordered 25 of each MJE15034/MJE15035 and also MJL4281/4302 and 5 each of MJL21195/96. Having all those old parts previously makes you appreciate the high end parts such as these.
Hello EWorkshop1708,
i know a lot of people who don't want to use secondhand components in their projects. I always get warned about using secondhand polarized capacitors as they can dry out and can explode. As i only use them for testing and at voltages way below their rating (EG : 200v electrode's running at a rail voltage of 40v ) and only for the testing period, i can't see any problems with that.
also with the money i save on discrete components i can buy better transistors for my testing.

When i was young on weekends my father used to pay the garbage man about 10 cents for any old radio, tv when we took our rubbish to the tip. This would keep me quiet for the whole weekend and when he went back to the tip he would take the remains of the tv and buy me another one to pull apart.
amazingly i still have some old valves from that time.

the thing that got me looking for electronic stuff people didn't want anymore was while i was down the rubbish tip dropping off some garden waste, i noticed a large pile of computer monitors from the telephone company. i asked the rubbish man if i could have one and the amount of useful items i found inside made me realize how much good useful stuff is getting buried in land fill every year.
out of that one monitor i got at least 6 handy size heat sinks that would have cost me about $20 which are perfect for mounting driver transistor on.
i wish i have piled the lot in a trailer, had i known what was inside.


2005-07-02 8:17 pm
65N 25E
Sometimes local junkjard is real treasury hunting. I am living in northern part of Finland but what I have heard from fellow DIY-people from south, junkjards are even better there. For example 100V 10mF caps mounted to busbars with invidual 20A fuses (high-breaking capacity ones$$), 48 beer-can size caps per unit! weery nice. 220/220 isolation transformers, 2kW variacs, rack hardware. Big heatsinks are difficult to find, always full of holes or silly shape. Actually i was planning to buy full 6 meter aluminium extrusion heatsink because you get full 6 meters with price of 40cm at electronics supplier.
And couple of years ago lots of NMT450/900 base station stuff, avesome power supplies and so on. Top quality telecom grade, off course. Or induction welding machine, water cooled IRFP460 mosfets, 30 pieces per side of aluminum bar, both sides, 2 aluminum bars per pcb, total 120 pcs big mosfets per pcb and a dozen of these pcb's in a housing.

What pisses me really off is that one specific company in my area is sucking all the electronics waste from electronics industry and they cant sell anything, everything goes trough mill to thousands pieces. Last time i visited there was 19" monitors, full truckload. And new golded SMA and BNC connectors, couple of hundreds :mad: . Some guy was just loading 5mm red and yellow leds to "meat grinder", had to be thousands of them send to destruction. :mad:


2005-07-02 8:17 pm
65N 25E
John Biles said:
Hello MZZJ,
Because the companies know that if they let people have access to these redundant components, they won't be buying new stuff from them, so they'd rather destoy it then see it put to good use.

it's always about profits, if someone found a way to make money by feeded the poor, there be no poverty in the world.
More likely in this case that local hitech-companies(Nokia for example) are affraid that their prototypes, firmwares and so on are leaking trough waste bin and they specify everything to be smashed, easier that way than start separating everything to classifield and non-classifield.
Another low cost source of parts ...

I tend to source my components as unused 'surplus' / 'end of production' or 'bankrupt stock'. This costs me a tiny fraction of the normal price and is a lot less effort than salvaged components (but not quite so low cost !!). For me, the initial cost of doing this was not insignificant but it has paid back many times over in the long run as buying in small quantities (in the UK) is very expensive.
My uncle once went to the university's surplus auction. He was very proud of himself because he thought he bought an electric piano for $50.00. But when he went to pay and pick it up, he found that he bought 12 electric pianos. 2 were unrepairable, and 2 had minor problems, but 8 worked perfectly.

He sold 9 of them for $75 to $125 each and kept the best one for himself.
When i was in high school,i used to collect any electronic junk from any one i know.But most of them are computer or video or tv related junks,but never a chance on any audio related stuff:cannotbe: Anyway,some of them are repairable and most are not.Spent much of my time on recycling those,ie desolder all the usable components,which some are rare or expensive.

But nowadays,not much seen young guys like me.Most of them learn electronic only through higher level education but most definitely not collecting junks like i did before:(
Hello Destroyer,
i agree that to me half the fun is finding what useful parts are inside something i been given and when you do find something that would normally cost you alot for nothing and you hear an amplifier you built out of the stuff and it cost you far less than would normally be the case, you feel good.
i have an old record player (AWA)13watt rms per channel built in 1973 that is solid state and is still working perfectly after 32years.
when i look at that and are pulling apart a monitor that was built in 1994 i think to myself that alot of these parts would mostly keep working for years to come if i built something out of them.


2004-06-08 8:58 am
Amp3 PSU

I found very cheap at a building recycling firm, a bundle of those lighting transformers used for the common 50 watt 12 volt halogen lamps. Nobody wants these now as electronic transformers are preferred.
With a simple rectifier/voltage regulator these are ideal for Amp3, giving 14.5 volts DC.
I had expected problems with noise/hum, but absolutely nothing, and quite good AC regulation too.
As I am building these into a very thin tower active speaker, their shape is ideal as well.
They come in 50VA and 100VA sizes.
Building a whole amp from recycled parts

I have built a few low powered "transistor radio" sized power amps, but no "real" ones. Actually I am hooked on the <3 transistor sound and old full ranges when optimized by experimentation. I have built quite a few phono preamps and some 2 transistor headphone amps, and the G Randy Sloan model headphone amp from his source book (IC model) which is actually a larger Class A power amp. I also build numerous RC circuits for passive filters, and passive headphone X-processors. And the most fun with recycling is testing electrolytics for age and leakage, especially with TV capacitors.

With recycled parts and an NTE cross reference or selector guide, your costs can be fractions of the regular cost. A filing and inventory system would be useful though.

With absolutely no cost, and voltages under 12 v, the resistor and capacitor values can be experimented with to get better results.

Almost 90% of the audio transistors used today can be chosen from a group of less than 20 transistors, especially when most small transistors end up crossing over to a 2N3904 or its complement. And it is surprizing how excellent the quality of componets are in some of the early equipment (like VCRs when they costed $1500 in the 80s), and professional test and video equipment. I get nothing but success with good quality salvaged components. And I have developed my own wiring and veroboard schemes to avoid etchant and PC boards. And when considering that we usually use short lengths for internal wiring, there is plenty available.

Crossovers can be experimented with to find exact components, by hooking caps back to back, using AC motor capacitors, and winding chokes from the copper from TV yokes, salvaged transformers, and deguassing coils.

Simple power OP amp IC's use very few parts to work, and almost every old TV or VCR will have power transformers that will work. Of course for higher powered OP amps a complicated or switching power supply is needed, but remember when dealing with high currents and over 9 volts DC, destroying componenets (and danger) can become "regular".

Follow lead (led) handling precautions, and don't breathe the lead-free fumes either.

Many books were published by SAMS and TAB that had hundreds of simple one evening <3 transistor projects.


2007-10-10 5:21 pm
I'm wondering if anyone actually built a whole Amplifier just out of recycled components?

The case and soup can caps came from the power supply for the disk drive of an old VAX. The trafo came from a copy machine and was rewound. Rectifier and heat sinks from a battery charger. The outputs are 2N3773 and were "pulls" purchased at Skycraft. The drivers are all mis-matched and came from various sources. Small signal transistors are all MPSA06 or MPSA56 which came from a pcb loaded with TTL chips and relays. Speaker terminals came from a burnt up receiver. All the caps and resistors came from the 'stash', which may or may not have been purchased new at one time.

It's a basic blameless, and puts out 60W/ch at 8R and a bit under 100 at 4. I've been using it to run DJ monitors.


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