Author Topic: total novice needs advice on zener diodes  (Read 1472 times)

0 Members and 1 Guest are viewing this topic.

Offline emmajacktTopic starter

  • Newbie
  • Posts: 4
  • Country: gb
total novice needs advice on zener diodes
« on: December 02, 2018, 11:54:54 pm »
Hi, I am a total novice when it comes to circuit boards and was wondering if someone could help me. I have a Horizon Omega CS treadmill and there was a loud bang when I plugged it in last week and the circuit board had blown a couple of transistors and a couple of zener diodes. As the diodes have blown, I am unable to test what voltage ones I would need to replace them. I am attaching a picture of the same diode that i need and would be really grateful if someone could help me. I have looked online for a diagram of the circuit board with no luck

Thank you, Kev.
« Last Edit: December 02, 2018, 11:56:54 pm by emmajackt »
 

Offline FriedMule

  • Frequent Contributor
  • **
  • Posts: 807
  • Country: dk
  • Can make even the simplest task look imposible.
Re: total novice needs advice on zener diodes
« Reply #1 on: December 03, 2018, 07:47:45 am »
I am a novice like you so my advice can be the worst thing to do but I would try to locate if there are some place where it says the voltage and then work backward and if that do not work I'll put ZD in with a wary low voltage and then put one with a higher voltage until it looks to work fine.
Even if I appear online is it not necessary so, my computer is on 24/7 even if I am not on.
 

Offline capt bullshot

  • Super Contributor
  • ***
  • Posts: 3033
  • Country: de
    • Mostly useless stuff, but nice to have: wunderkis.de
Re: total novice needs advice on zener diodes
« Reply #2 on: December 03, 2018, 08:00:56 am »
If you just want to replace the diodes and transistors, you'll have to get some documentation or information from the manufacturer or a very similar unit. I don't have either of these.

Otherwise, one would try to reverse parts of the schematic to get an idea of what is the purpose of these diodes, why they were blown and make an educated guess on their value.
Safety devices hinder evolution
 

Offline mvs

  • Frequent Contributor
  • **
  • Posts: 370
  • Country: de
Re: total novice needs advice on zener diodes
« Reply #3 on: December 03, 2018, 09:49:15 am »
the circuit board had blown a couple of transistors and a couple of zener diodes
ZD1 is a Zener diode designator, but D12 is not. If it was also in glass DO-35 package, it might be 1N4148.
If you make good photos of the board from both sides, perhaps we can derive components from their functions.
 

Offline emmajacktTopic starter

  • Newbie
  • Posts: 4
  • Country: gb
Re: total novice needs advice on zener diodes
« Reply #4 on: December 03, 2018, 08:16:46 pm »
Hi, thank you for your replies. I have attached a few more pictures of the whole board and a picture of the diodes that I need, from a picture I found online. The treadmill is quite old and not worth spending ££s on it. I really appreciate your answers. I thought it would be a case of replacing the two blown diodes, one blown resistor and the two transistors and hoping for the best, but obviously there's more involved and I cannot find a schematics for the treadmill anywhere.

Regards, Kev
 

Offline Johnny10

  • Frequent Contributor
  • **
  • Posts: 899
  • Country: us
Re: total novice needs advice on zener diodes
« Reply #5 on: December 03, 2018, 09:20:17 pm »
It looks to me as though you might be able to buy boards and replace.

 The Omega II manual has pics of PC board but no schematic.

http://productload.johnsonfit.com/inc/uploaded_media/ba2e870dabd6373a48f8e138dfc9c56f/service_guide/54c14b21a33d970fb0beb252b7d83034.pdf


I don't know your exact Model number but look here.

https://www.ereplacementparts.com/horizon-fitness-treadmill-parts-c-201405_201552.html


Oh, But they are over $250 for Motor Controller Boards... OUCH !

Sorry, Guess I wasn't much help.
 Or these guys charge about $75 to do repair.
I saw them on eBay.


« Last Edit: December 03, 2018, 09:55:19 pm by Johnny10 »
Tektronix TDS7104, DMM4050, HP 3561A, HP 35665, Tek 2465A, HP8903B, DSA602A, Tek 7854, 7834, HP3457A, Tek 575, 576, 577 Curve Tracers, Datron 4000, Datron 4000A, DOS4EVER uTracer, HP5335A, EIP534B 20GHz Frequency Counter, TrueTime Rubidium, Sencore LC102, Tek TG506, TG501, SG503, HP 8568B
 

Offline emmajacktTopic starter

  • Newbie
  • Posts: 4
  • Country: gb
Re: total novice needs advice on zener diodes
« Reply #6 on: December 03, 2018, 09:53:45 pm »
Wow!! I think the treadmill is only worth £30. Thanks so much for finding this though. Much appreciated.

Regards, Kev.
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 12288
  • Country: au
Re: total novice needs advice on zener diodes
« Reply #7 on: December 04, 2018, 12:49:32 am »
A word of warning ... even if you do correctly identify the failed parts and replace them, the questions still stands: Why did they fail?

If the fault condition was in one of those components that were replaced, then you have a fair chance that the replacements will fix the problem - but if it was not, then the replacement components might also meet an inglorious death.

... and you will be back where you are right now.
 

Offline capt bullshot

  • Super Contributor
  • ***
  • Posts: 3033
  • Country: de
    • Mostly useless stuff, but nice to have: wunderkis.de
Re: total novice needs advice on zener diodes
« Reply #8 on: December 04, 2018, 06:33:52 am »
Looks like this board does some serious mains voltage control. Having small components going bang on such kind of board usually has its root cause somewhere else, not the components itself.
Safety devices hinder evolution
 

Offline emmajacktTopic starter

  • Newbie
  • Posts: 4
  • Country: gb
Re: total novice needs advice on zener diodes
« Reply #9 on: December 04, 2018, 11:54:12 am »
Thank you for all of your advice. I think this repair is beyond my very limited electronics knowledge, so instead of wasting money, I think I will scrap it and look on Ebay for another.

Thanks again for all your replies and have a great Christmas.

Regards, Kev.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf