News:

Welcome to C5alive, the best place for help & advice on how to get the most from your iconic Sinclair C5. Check the meetings section today for events near you.
C5alive.co.uk  - Keeping the C5 Alive !!


Author Topic: Replacement components?  (Read 3347 times)

0 Members and 1 Guest are viewing this topic.

Offline teamgardner

  • Newbie
  • Posts: 29
  • Battery level: 1
  • 4 legs may be better than 2 but 3 wheels better then anything!
Replacement components?
« on: 21, May, 2012 - 21:30:49 »
Hi, I replaced some components with some alternatives. So far everything sees okay so I thought I'd put them up.

ZD1 in control box replaced by BZY88C24

TR1 & 2 In the pod replaced by BC557

I am not experienced with electronics so if anyone spots a problem with these can they let me know.

Offline radiomarty

  • Administrator
  • Millennium Member
  • *****
  • Posts: 2641
  • Battery level: 100
Re: Replacement components?
« Reply #1 on: 21, May, 2012 - 22:12:59 »
Off the top of my head bud without looking up the data sheets - the originals were a matched pair of NPN and PNP transistors therefore replacing them with the same for tr1 and tr2 wont work - you need the matched opposite of the BC557  ie AN BC547 thus giving you a matched PNP AND NPN  pair - also need to check voltages and switching currents - PS I use the originals that are easily obtainable

Offline teamgardner

  • Newbie
  • Posts: 29
  • Battery level: 1
  • 4 legs may be better than 2 but 3 wheels better then anything!
Re: Replacement components?
« Reply #2 on: 21, May, 2012 - 22:44:57 »
Whoops! Glad you guys are here to help.
I couldnt find the originals anywhere. Do you you know where to get them from. I'd better swap them back

Offline radiomarty

  • Administrator
  • Millennium Member
  • *****
  • Posts: 2641
  • Battery level: 100
Re: Replacement components?
« Reply #3 on: 21, May, 2012 - 22:46:24 »
Search them on e-bay - always available on there - Marty :)

Offline teamgardner

  • Newbie
  • Posts: 29
  • Battery level: 1
  • 4 legs may be better than 2 but 3 wheels better then anything!
Re: Replacement components?
« Reply #4 on: 21, May, 2012 - 22:51:17 »
Thats where I've been looking. I just tried and still cant get anything. I'm searching for fst290

marra

  • Guest
Re: Replacement components?
« Reply #5 on: 21, May, 2012 - 22:53:45 »
Search them on e-bay - always available on there - Marty :)

hi marty, could you give a link(s) please. thanks m

Offline radiomarty

  • Administrator
  • Millennium Member
  • *****
  • Posts: 2641
  • Battery level: 100
Re: Replacement components?
« Reply #6 on: 21, May, 2012 - 23:00:49 »
OPPS - JUST REALISED YOUR TALKING ABOUT THE POD NOT CONTROL BOX DOOOOOOOOOOOOOOOOOOOH

Offline teamgardner

  • Newbie
  • Posts: 29
  • Battery level: 1
  • 4 legs may be better than 2 but 3 wheels better then anything!
Re: Replacement components?
« Reply #7 on: 21, May, 2012 - 23:04:20 »
You had me worried there. I thought I was going daft.

Offline radiomarty

  • Administrator
  • Millennium Member
  • *****
  • Posts: 2641
  • Battery level: 100
Re: Replacement components?
« Reply #8 on: 21, May, 2012 - 23:06:21 »
In that case i think they are suitable thanks for sharing them and sorry about my senior moment - i need some sleep !!!!!

Offline KarlG

  • Hero Member
  • ****
  • Posts: 553
  • Battery level: 8
  • You don't have to be mad to own a C5, but it helps
Re: Replacement components?
« Reply #9 on: 24, September, 2012 - 22:52:03 »
Hi teamgardner,

Quote
TR1 & 2 In the pod replaced by BC557

I recommend that you change 'BC557' to 'BC557C'.  This is the transistor that Phil quoted.

The reason for this is the parameters for the 557 are not the same as a 557C.

The gain (hfe), or the amplification, are not the same. Check the following:

BC557    minimum gain is 125
BC557B       "           "    "  220
BC557C       "           "    "  420

In a worst case scenario you fit a 557 that has the min. gain you could end up with the system not working correctly.

Regards.

KarlG.



Offline teamgardner

  • Newbie
  • Posts: 29
  • Battery level: 1
  • 4 legs may be better than 2 but 3 wheels better then anything!
Re: Replacement components?
« Reply #10 on: 27, September, 2012 - 12:14:08 »
thanks Karl. I have had no problems with the pod but if i do get problems now i will know why.