I own a wireless guitar system that operates at 170.245 MHz. My transmitter broke, but the receiver still works. I am looking for schematics for a simple transmitter of the same frequency that will accept a High Z guitar signal and will broadcast about 100 to 150 feet. Any ideas appreciated.
Have you looked into fixing the broken transmitter? Probably would be lots easier than finding a suitable replacement... assuming that it's not potted or just a microcircuit under a blob of epoxy.
Barring that, is the transmitter AM or FM? if it's FM, how much deviation does it require? What's the audio signal level from the guitar? What kind of pickup(s) does it have?
-- Dave M MasonDG44 at comcast dot net (Just subsitute the appropriate characters in the address)
Buy a new system for $100 and you'll have a spare receiver.
Not knocking the DIY approach, but given the price of these things new it would have to be a labour of love...
--
*If only you'd use your powers for good instead of evil.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
How? Transmits carrier but no audio? No carrier or audio? Totally dead? Drove over it in the car? If it's anything but the latter it could well be fixable, especially if you are competent enough to consider building one!
Forget it. Building a small transmitter with rock steady frequency, spectrally clean output, wide modulation sufficient for hi fi sound quality, properly matched to a guitar pickup, reliable and with very low power consumption in not trivial for anyone but an experienced designer. Even then it would be a fairly big project.
Not to mention that in many/most countries such a home made unit would breach radio licensing regulations.
Sure, there are designs for quick and dirty wireless 'bugs' which will transmit an audio signal, some with quite good fidelity, onto an FM broadcast receiver. However, these are simple free running oscillators which drift like a drifty thing and throw out a lot of RF dirt.
There's only two satisfactory ways of achieving satisfactory results IMO- get the transmitter repaired, either professionally or by someone competent, or buy a new one.
Why not post details of the fault here? Maybe we can offer some help fixing it.
Dave
No problem - that is how we learn. Sometimes the lessons are more expensive than yours was...so be grateful for that.
I've dropped some right clangers in my time, like cracking the screen on a £1000 laptop I was repairing when I fell off the chair ;-) Humiliation is part of electronics!
So you buy a cheap solder sucker, a few quid/bucks/euros/whatever, remove the solder in the area where it flooded and start again!
You might as well try and repair the old one, what have you got to lose? If nothing else you'll get some practice at soldering.
Dave
There is a very small rectangular 'jumper?' that was fried. I do not know what they are, but all circuit boards seem to have them. Diode, resistor, whatever it is, it is destroyed. Can I jumper across with a wire?
Robert
Most likely it isn't a jumper, it is a component.
The answer is no.
No, don't jumper across it under any circumstances. Can you describe the component exactly? Size, appearance, how many 'legs', is it a wired component or is it surface mount? Where in the circuit is it located? Near the aerial, near the battery leads/contacts, near the audio in?
If it is a resistor, chances are it burned up because of a shorted transistor, IC or capacitor etc.
If you have webspace, is there any chance you could put the unit on a scanner and upload it? A digital camera will do but a scanner gives a much better image with PCBs IMO. A scan of both sides of the PCB would be great.
If you don't have webspace, I can give you an email address you can send the image to.
Dave
a
Most likely it isn't a jumper, it is a component.
The answer is no.
a
No, don't jumper across it under any circumstances. Can you describe the component exactly? Size, appearance, how many 'legs', is it a wired component or is it surface mount? Where in the circuit is it located? Near the aerial, near the battery leads/contacts, near the audio in?
If it is a resistor, chances are it burned up because of a shorted transistor, IC or capacitor etc.
If you have webspace, is there any chance you could put the unit on a scanner and upload it? A digital camera will do but a scanner gives a much better image with PCBs IMO. A scan of both sides of the PCB would be great.
If you don't have webspace, I can give you an email address you can send the image to.
Dave
Possibly a semiconductor/SS fuse?
Tom
I can photograph it and post it somewhere in a couple of days. I have to go out of town tomorrow, but only overnight. I'll post the web address here after I post the picture (probably at flickr.com or yahoo). The unknown component is about .5 mm by 1 mm in size, and it sticks out about .5 mm from the board. It is silver-colored at each end and black in the middle, and it only connects in one place at either end, like a jumper. I have no idea what those things are, but there are several of them on the back side of the circuit board.
Robert
That sounds like a surface mount resistor. It may be difficult to impossible to repair without a schematic, but I'll have a look at the picture anyway when you post it. It is sometimes possible to arrive at a suitable resistor value using "suck it and see" techniques, and by using an educated guess by examining the circuit. However, this resistor certainly did not fail on its own, there will be damage elsewhere as well.
Dave
Not to be negative, but....
The OP doesn't have a schematic, and doesn't have SMT skills or tools.
Good luck.
I know, it's probably a dead loss.
Dave
Does *anyone* have SMT skills? ;-)
--
*How do you tell when you run out of invisible ink? *Dave Plowman snipped-for-privacy@davenoise.co.uk London SW To e-mail, change noise into sound.
Yes I have SMT repair skills. The Navy Depot repair facility where I work at regularly trains and certifies techs in micro-miniature soldering and repair tools and skills. We all must pass a pretty difficult test in order to retain our certs and remain on the bench.
-- Dave M MasonDG44 at comcast dot net (Just subsitute the appropriate characters in the address)
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