mosfet replacement for tip120?

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im working on a arcade game board . the tip 120 for an eject soleniod  is driven right off the processor leg, no pre -driver transistor. didnt even think that was possible, maybe that why it blew.   is there a mosfet i can replace the tip120 with?  

thanks

Re: mosfet replacement for tip120?
On Wednesday, September 13, 2017 at 11:35:58 AM UTC-4, snipped-for-privacy@gmail.com wrote:
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So a 5 V drive?  You could look up logic level mosfets on digikey.  
Is there a diode across the solenoid drive?  (for inductance)

George H.

Re: mosfet replacement for tip120?

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The TIP120 is a medium power darlington NPN rated for 60 volts. It has the  
reverse diode built in.




Re: mosfet replacement for tip120?
On Wednesday, September 13, 2017 at 12:25:30 PM UTC-4, tom wrote:
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Huh, thanks.  I knew it is a darlington, I didn't know about the diode.  
Still you might want to add a diode on the coil... I'm a belt and suspenders
type.  

George H.  

Re: mosfet replacement for tip120?
In article <1d24b048-8665-4621-bd51-
snipped-for-privacy@googlegroups.com>, snipped-for-privacy@gmail.com  
says...
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Why not just buy the tip 120 ?  They are only from about  
$ .50 to $ .75 from several big dealers.

Even ebay has what you want for less than $ 6 for 5 of  
them including shipping.  The larges cost is the $ 4 for  
shipping  That the arcade game machine is mentione in.

http://www.ebay.com/itm/Qty-5-TIP120-Williams-Pinball-
Coil-Driver-Transistors-/251525068084?epid12%31714050
&hash=item3a900ff534:g:XX8AAOSw8d9UuyQx




Re: mosfet replacement for tip120?
On Wed, 13 Sep 2017 08:33:57 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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I don't like using darlingtons for power drivers.  A momentary shorted
load, and the darlington blows up from too much current.  This article
should provide some detail:
<http://www.sensitiveresearch.com/elec/DoNotTIP/index.html
I can't offer any specific recommendations without some clue as to the
processor output voltage and current capabilities, the solenoid specs,
and the operating voltage.


--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: mosfet replacement for tip120?
On Wednesday, September 13, 2017 at 8:29:21 PM UTC-4, Jeff Liebermann wrote:
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I use a TIP120 in a lamp heater (Rubidium lamp).  It's nailed  
right to the lamp housing (besides a power resistor that shares the work.)
Works great.  It must be a fairly robust piece of silicon, 'cause I've used it to raise the lamp temperature to 150 C and let it run for days like that.  
(typical operation temp is 120 C.. for years.)  

George H.  

Re: mosfet replacement for tip120?
:
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s driven right off the processor leg, no pre -driver transistor. didnt even
 think that was possible, maybe that why it blew.   is there a mosfet i can
 replace the tip120 with?  
Quoted text here. Click to load it



I wouldn't worry about using a Darlington as a coil driver.  Arcade games a
re generally quite robust (the monitors generally the weakest point) and th
ey've been using them for years with no issues.  They used to use relays or
 even high current leaf switches to drive coils but relays and switches hav
e a finite life.


Re: mosfet replacement for tip120?
On 2017/09/14 6:46 AM, John-Del wrote:
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Well, actually. no, arcade games (pinball games) using TIPs and other  
BJTs have a nasty habit of failing and cooking their coils and the  
circuit board. Many of us in the trade are getting around to finally  
ripping out all these dinosaurs and replacing them with modern devices.  
It has taken me far too long to realize I am not doing customers a  
favour by leaving old tech in their games. As the link Jeff provided you  
get up to 4VDC drop across the BJT so a MOSFET with less than 1V drop  
will give you more pop too!

Most of the aftermarket replacement boards are using MOSFETs except for  
a few holdouts whose quality suffers in other areas too.

Still for the OP who has a CHEXX game the TIP120 should last forever, it  
has at most a 1A draw, and we have never replaced one in the 30 odd  
years I've been servicing CHEXX boards.

John :-#)#
--  
(Please post followups or tech inquiries to the USENET newsgroup)
                      John's Jukes Ltd.
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Re: mosfet replacement for tip120?
On Thursday, September 14, 2017 at 1:10:23 PM UTC-4, John Robertson wrote:
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rote:
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  is driven right off the processor leg, no pre -driver transistor. didnt e
ven think that was possible, maybe that why it blew.   is there a mosfet i  
can replace the tip120 with?
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es are generally quite robust (the monitors generally the weakest point) an
d they've been using them for years with no issues.  They used to use relay
s or even high current leaf switches to drive coils but relays and switches
 have a finite life.
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From about 1982 until he sold the company about 8 years ago, I did all the  
electrical work for a vendor who became a very good friend of mine.  The va
st majority of the work I did for him were monitor failures.  Most of the e
lectrical work he did was swapping out game boards, converting cabinets and
 replacing hard drives. He would shop the pinballs as they were rotated or  
were pulled for failures and if there was a problem beyond lamps, rubbers,  
solenoids etc. I'd get the board.  

I rarely saw shorted Darlingtons.  I agree that MosFets are better suited t
o switching, but other than upgrading the ratings of the replacements, we n
ever felt the need to do wholesale replacements of Darlingtons that would m
ost likely last the life of the game. It was far easier to deal with them i
ndividually.

Re: mosfet replacement for tip120?
On 2017/09/14 2:57 PM, John-Del wrote:
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I hear what you are saying, but when you run into boards where most of  
the transistors show signs of overheating the PCB (Atari lamp driver Aux  
board for example) then one considers replacing the old BJTs with more  
modern devices to improve the expected lifespan.

John :-#)#

--  
(Please post followups or tech inquiries to the USENET newsgroup)
                      John's Jukes Ltd.
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Re: mosfet replacement for tip120?
On Thursday, September 14, 2017 at 6:15:15 PM UTC-4, John Robertson wrote:
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te:
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 wrote:
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od  is driven right off the processor leg, no pre -driver transistor. didnt
 even think that was possible, maybe that why it blew.   is there a mosfet  
i can replace the tip120 with?
Quoted text here. Click to load it
ed
le
he
s,
ames are generally quite robust (the monitors generally the weakest point)  
and they've been using them for years with no issues.  They used to use rel
ays or even high current leaf switches to drive coils but relays and switch
es have a finite life.
Quoted text here. Click to load it
.
ou
r
it
 the electrical work for a vendor who became a very good friend of mine.  T
he vast majority of the work I did for him were monitor failures.  Most of  
the electrical work he did was swapping out game boards, converting cabinet
s and replacing hard drives. He would shop the pinballs as they were rotate
d or were pulled for failures and if there was a problem beyond lamps, rubb
ers, solenoids etc. I'd get the board.
Quoted text here. Click to load it
ed to switching, but other than upgrading the ratings of the replacements,  
we never felt the need to do wholesale replacements of Darlingtons that wou
ld most likely last the life of the game. It was far easier to deal with th
em individually.
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Quoted text here. Click to load it

Wow, that triggered an old memory.  I do remember adding heatsinks to all t
he TO-202 free standing driver transistors on certain boards many years ago
, but don't recall which one. Stern pin maybe?

But I suppose changing all the transistors over to mosfets in 30 year old g
ames in 2017 is analogous to doing wholesale capacitor replacement in old r
adios. I guess age catches up to everything.

  

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