The pulser circuit on my Mattel has stopped pulsing and I found that one of these tantalum capacitors has failed - tested as open circuit.
I just need to be sure of the value. It's brown and black bands with a white dot. So is that 0.1uf? The band that indicates the voltage rating is a tan colour but can't find a value for it. Any ideas? Looks more grey in the photo.
Thanks for any help,
Carl
Mattel Transmitter Help
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Mattel Transmitter Help
Last edited by Carl on 25 Apr 2018, 14:13, edited 1 time in total.
Carl
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Re: Help Identifying a Capacitor
Thanks Phil for the info. My brain was working backwards last night
One capacitor shows open and the other a resistance. I did another test by applying a voltage to each and then checked the voltage stored. The one that shows as open gave a voltage reading on the multimeter and the one with a resistance doesn't give a voltage reading and guess this second capacitor is the faulty one.
So it looks as tough we've found the culprit. Hopefully replacing the two capacitors will bring the pulser circuit back to life
Thanks again Phil,
Carl
Carl
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Re: Help Identifying a Capacitor
Just ordered a small pack of 1uf 16v tantalum capacitors.
Carl
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Re: Help Identifying a Capacitor
That colour coding was a blast from the past.
A while back I purchased a cheap component tester that can be used to check a variety of components such as resistors, transistors and yes you've guessed it capacitors. It may be worth considering purchasing one if you plan on more renovations.
A quick search on Ebay should result in a wide choice to suit depth of pocket.
Ade
A while back I purchased a cheap component tester that can be used to check a variety of components such as resistors, transistors and yes you've guessed it capacitors. It may be worth considering purchasing one if you plan on more renovations.
A quick search on Ebay should result in a wide choice to suit depth of pocket.
Ade
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Re: Mattel Transmitter Help
Thanks for your help so far I say so far as the pulser circuit still isn't pulsing. I checked the caps I put in are good to eliminate them. There are two npn transistors in the circuit, so took those out and have found one of them had failed also
They are 2SC537E and are unavailable. Looking up online for an equivalent returns NTE289A, but can't get these in the UK. Anyone suggest an alternative? Or anyone have either in your stash that you'd be willing to sell me? Or even have a board taken out of a converted transmitter - I do remember someone did a conversion but that's lost on the previous forum.
Thanks again,
Carl
They are 2SC537E and are unavailable. Looking up online for an equivalent returns NTE289A, but can't get these in the UK. Anyone suggest an alternative? Or anyone have either in your stash that you'd be willing to sell me? Or even have a board taken out of a converted transmitter - I do remember someone did a conversion but that's lost on the previous forum.
Thanks again,
Carl
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Re: Mattel Transmitter Help
TUP TUN DUG DUS
When Elektor was in its heyday they came up with a term for general purpose, non-critical applications -
TUP - transistor, universal, PNP
TUN - transistor, universal, NPN
DUG - diode, universal, germanium
DUS - diode, universal, silicon
What you need Carl is a couple of TUN's - 2N3904, BC107/108/109/184, ZTX300, and many, many more alternatives. You dont need an exact equivalent for a simple pulser.
When Elektor was in its heyday they came up with a term for general purpose, non-critical applications -
TUP - transistor, universal, PNP
TUN - transistor, universal, NPN
DUG - diode, universal, germanium
DUS - diode, universal, silicon
What you need Carl is a couple of TUN's - 2N3904, BC107/108/109/184, ZTX300, and many, many more alternatives. You dont need an exact equivalent for a simple pulser.
- Attachments
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- TUP-TUN-DUG-DUS-elektor.pdf
- (66.01 KiB) Downloaded 160 times
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Re: Mattel Transmitter Help
Thanks Phil, I was hoping one of you electronics geniuses would say that. I have some BC108s and will give them a go.
Carl
Carl
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Re: Mattel Transmitter Help
Thanks Phil, that's another vintage transmitter back in action You might remember you gave assistance for the receiver for this very set.
That was a very useful pdf you provided. I remember Elektor as a lad. My father must have purchased that mag as he was an electronics man and had a tv repair business in the days when you had them repaired.
Carl
That was a very useful pdf you provided. I remember Elektor as a lad. My father must have purchased that mag as he was an electronics man and had a tv repair business in the days when you had them repaired.
Carl
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Re: Mattel Transmitter Help
G0MBV Class A Radio Amateur, North Yorkshire
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Re: Mattel Transmitter Help
Sorry Ron, I forgot you repair tvs. It explains why you turn out such cracking transmitters.
Carl
Carl
Carl
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