Looking for a schematic, or help, for a Mattel pulse transmitter. Made in 1971. There is a problem in the final amplification stage. I can see low frequency pulsing, using my oscilloscope, and some high frequency around the crystall but the mixture of the 2 is lost near the last transister before the antenna.

I'm attempting to get my first radio going. I bought it in the late 70's from AHC for my Ace/House of Balsa Nomad I built back then but didn't fly because of transmitter issues. Blowing off the dust after 30+ years! LOL

Thanks for any help! I'll be adding info here as I find it.

You might do well to talk to Shaun and Phil at
www.singlechannel.co.uk

Thank you!

I'd also be interested in any documentation on the Mattel radio. I too still have one from the 70s and would like to fly it again.

I still have my Ace Pulse Commander transmitter and receiver but don't have a good Adams baby twin actuator or electronics skills to get it working properly.

http://www.ebay.com/itm/MATTEL-SIGNA...item3a7a9c3a31

On ebay now. One day left...

I am forever amazed what I find, by accident, in forums! Where did you find those schematics? I repaired my receiver 2 years ago, I could have used that schematic! It had exploded a transistor back in 1980 or so, after the Ace glider was recovered form a wet place, and I applied too much voltage. I wonder if your TX is really OK? I used a walkie talkie channel 14 (A CB could work) to listen to its signal, it was low frequency with tapping beep noise changing with rudder stick position. Steadier tone as stick moved to stops. Then I knew it was OK and I could fix the RX.

Originally Posted by pspring

Looking for a schematic, or help, for a Mattel pulse transmitter. Made in 1971. There is a problem in the final amplification stage. I can see low frequency pulsing, using my oscilloscope, and some high frequency around the crystall but the mixture of the 2 is lost near the last transister before the antenna.

I'm attempting to get my first radio going. I bought it in the late 70's from AHC for my Ace/House of Balsa Nomad I built back then but didn't fly because of transmitter issues. Blowing off the dust after 30+ years! LOL

Thanks for any help! I'll be adding info here as I find it.

To help you I need some information.
The transmitter system in which Mattel final output frequency band 27Mhz? Most probably it is because the old system.
The plan shows oscillator working third harmonics(overtone) in 27Mhz.
The crystal then has real Oscillation 9Mhz X third harmonics(overtone) = 27mHZ.

Then the transformer (coil) OC, has problems or will coordinate.
Can not muzzle frequency tripling and driving in the final output transistor transmitter.
Primary winding coil OC = frequency tripling.
Secondary coil OC = the output transistor driving 2SC423E.
Got frequency meter apart oscilloscope to measure frequency?

Awaiting a response.

Elijah Greece.

Did a lot of poking around the internet and asking on other forums for those schematics. I am compiling what I find in one place for future reference and sharing.

Once my Tx is fixed was thinking of putting up some pics of various waveforms for the Tx and Rx. Not everyone has a scope though so I was also going to do some voltage measurements. I did go to 2 years of electronic tech school many years ago but we didn't study RF. I'm learning some basics just to be able to maybe tune up some old equipement like this easy Mattel circuit.

hlstat: Yes 27Mhz. The transistor driving the antenna seems bad. It seems open. I do not get .7v across junctions using a diode tester. I am looking for a replacement in my junk pile.
I did measure the frequency at the coil driving the output transistor and it matched the frequency sticker on the transmitter.
I'm interested in learning what the various coils do in the Tx circuit shown above and how to tune for best performance. It seems like you know a bit in that area?

Thanks!

The Mattel system was also responsible for my first successful RC adventure, back in 1975 when America's Hobby Center was liquidating the Mattel systems for only $19.95. I eventually taught myself how to fly using the Mattel in a Jr. Falcon. Back in 2000, I recreated the experience with my original transmitter and a Jr Falcon built from plans. I didn't have an extra Mattel receiver for it but I discovered that any cheap 27 MHz toy car receiver would also work, so I picked one up from Radio Shack and modified it to drive the actuator. I've flown this many times with no problem using the Radio Shack receiver.

Steve

Nice looking Falcon! I always wanted to build one. Someday...

Interesting idea about the Radio Shack rx. I have one from an old car that does the turn in reverse thing when the Tx button is pressed. Should be perfect for a pulser. LOL I'll have to check the frequency...

hlstat: Yes 27Mhz. The transistor driving the antenna seems bad. It seems open. I do not get .7v across junctions using a diode tester. I am looking for a replacement in my junk pile.
I did measure the frequency at the coil driving the output transistor and it matched the frequency sticker on the transmitter.
I'm interested in learning what the various coils do in the Tx circuit shown above and how to tune for best performance. It seems like you know a bit in that area?

Thanks![/QUOTE]

Dear friend pspring.

Thanks for the good words.
I am a Mechanical Electronics.( Real Job )
First download the file image jpeg with the new clean plan and markings.
Second download Pdf file with the Service Information for you.
Good effort for service.
If you need something written here or send a private message to me.
Sorry for my English but I'm Greek man.

Elijah Greece.

Elijah, thank you! I am in your debt! I will first replace all electrolytic capacitors as maintenance. I have found a slight circuit difference in my unit. There is a .47 ohm resistor added to the base of the output transistor. Probably to limit the base current. I will let you know what I find in a day or two. Thanks again!

Originally Posted by mlbco

The Mattel system was also responsible for my first successful RC adventure, back in 1975 when America's Hobby Center was liquidating the Mattel systems for only $19.95. I eventually taught myself how to fly using the Mattel in a Jr. Falcon. Back in 2000, I recreated the experience with my original transmitter and a Jr Falcon built from plans. I didn't have an extra Mattel receiver for it but I discovered that any cheap 27 MHz toy car receiver would also work, so I picked one up from Radio Shack and modified it to drive the actuator. I've flown this many times with no problem using the Radio Shack receiver.

Steve

Steve,

Could you give us some more details on this? Those receivers that came with the Mattel units are huge. I'm sure the new stuff is small.

Thanks,

John

My first rc attempt was the Mattel pulse control on a baby Tri-Squire with an 0.049. Shortly after I launched it, I had no control and it flew away over Rock Creek Park north of the DC beltway in Maryland with the engine still screaming. I jumped in my car and headed west and cruised the neighborhood on the west side of Rock Creek Park and after an hour of looking, was about to call it a day, when I caught a glimpse of white in the backyard of a house. She had landed there with no damage except for the wing popping off (held on with rubber bands). I grabbed her and took her home and installed a proper ACE system--she was always in control after that!!!