Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > General Electronics Technical Discussion
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 02-20-2021, 09:42 AM   #1
Bibdid
New Member
 
Join Date: Jun 2019
City & State: Leicester/Sheffield
My Country: UK
I'm a: Knowledge Seeker
Posts: 6
Default Help substituting avalanche diode

repairs on an old CRT tv from the 80s that blew a flyback have led me to this diode which is reading near 0 in both directions. The diode is marked as an R2KY avalanche diode but is no longer manufactured.

I am fairly new to the world of electronics, could anyone help me source a suitable modern-day equivalent diode?


The datasheet of the diode can be found from
https://datasheetspdf.com/pdf/220430...ctorInc/R2KY/1

many thanks : )
Bibdid is offline   Reply With Quote
Old 02-20-2021, 12:19 PM   #2
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 24,373
Default Re: Help substituting avalanche diode

do you have a schematic to show where it was used?
stj is offline   Reply With Quote
Old 02-20-2021, 12:32 PM   #3
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,978
Default Re: Help substituting avalanche diode

You can get one from here: https://www.ebay.co.uk/itm/R2KY-ZENE...-/192164981448
R_J is offline   Reply With Quote
Old 02-20-2021, 02:27 PM   #4
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 24,373
Default Re: Help substituting avalanche diode

NIKKO??? good luck.
that guy is down the road - he is hardly open and often exagerates stock.
but you may get lucky.
stj is offline   Reply With Quote
Old 02-20-2021, 06:12 PM   #5
Bibdid
New Member
 
Join Date: Jun 2019
City & State: Leicester/Sheffield
My Country: UK
I'm a: Knowledge Seeker
Posts: 6
Default Re: Help substituting avalanche diode

Quote:
Originally Posted by stj View Post
do you have a schematic to show where it was used?
unfortunately not. The tv is a Mitsubishi ct 2043B although it seems to be really obscure.


The diode is connected to a voltage regulator. I will have a look at making a schematic in the next few days : )
Bibdid is offline   Reply With Quote
Old 02-20-2021, 06:15 PM   #6
Bibdid
New Member
 
Join Date: Jun 2019
City & State: Leicester/Sheffield
My Country: UK
I'm a: Knowledge Seeker
Posts: 6
Default Re: Help substituting avalanche diode

Quote:
Originally Posted by R_J View Post
Thanks, although I am a little worried that he states the part is 160v 1a as I'm sure the part should be 120v 2A?

I may give it a go though.
Bibdid is offline   Reply With Quote
Old 02-20-2021, 06:23 PM   #7
petehall347
Badcaps Veteran
 
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 2,679
Default Re: Help substituting avalanche diode

Quote:
Originally Posted by Bibdid View Post
unfortunately not. The tv is a Mitsubishi ct 2043B although it seems to be really obscure.


The diode is connected to a voltage regulator. I will have a look at making a schematic in the next few days : )
what is the board number ? will be something like vestel------- or maybe Haier -----
there is a schematic but asks to sign up . http://freebodydiagram.archivioprimo...our-television

Last edited by petehall347; 02-20-2021 at 06:27 PM..
petehall347 is offline   Reply With Quote
Old 02-20-2021, 06:39 PM   #8
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,978
Default Re: Help substituting avalanche diode

I believe it is just for over voltage protection on the +112 volt line to the horz. output section. I would replace the low voltage/capacity electrolytics in the primary, If they are bad the power supply might not regulate properly, it could also be bad caps on that B+ 112v line, If the caps go open the voltage can go up. You should be able to use the NTE570
Check the schematic for the CT-2153

Last edited by R_J; 02-20-2021 at 07:05 PM..
R_J is offline   Reply With Quote
Old 02-25-2021, 08:21 AM   #9
Bibdid
New Member
 
Join Date: Jun 2019
City & State: Leicester/Sheffield
My Country: UK
I'm a: Knowledge Seeker
Posts: 6
Default Re: Help substituting avalanche diode

Quote:
Originally Posted by petehall347 View Post
what is the board number ? will be something like vestel------- or maybe Haier -----
there is a schematic but asks to sign up . http://freebodydiagram.archivioprimo...our-television
That looks promising but the site seems to be very shady. Relinks me to scam sites.

I have attached some board model/serial numbers although it seems very obscure.
Attached Images
File Type: jpg 20210225-135803.jpg (697.3 KB, 11 views)
File Type: jpg 20210225-135752.jpg (305.3 KB, 9 views)
Bibdid is offline   Reply With Quote
Old 02-25-2021, 08:38 AM   #10
Bibdid
New Member
 
Join Date: Jun 2019
City & State: Leicester/Sheffield
My Country: UK
I'm a: Knowledge Seeker
Posts: 6
Default Re: Help substituting avalanche diode

Quote:
Originally Posted by R_J View Post
I believe it is just for over voltage protection on the +112 volt line to the horz. output section. I would replace the low voltage/capacity electrolytics in the primary, If they are bad the power supply might not regulate properly, it could also be bad caps on that B+ 112v line, If the caps go open the voltage can go up. You should be able to use the NTE570
Check the schematic for the CT-2153
Thanks for the help. I measured the capacitance and esr of a few capacitors around that area and they are way out of spec. Is it possible that these caps took out the flyback? I know this tv has had a very hard life and the flyback exploded somewhat violently, with resin being thrown out a fair distance onto the board.

As for the schematic, is there any reason you recommend the CT-2153 over others, just out of curiosity?
Bibdid is offline   Reply With Quote
Old 02-25-2021, 08:40 AM   #11
petehall347
Badcaps Veteran
 
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 2,679
Default Re: Help substituting avalanche diode

. cant make sense out of the board numbers yet .. maybe there are more numbers or a sticker

Last edited by petehall347; 02-25-2021 at 08:50 AM..
petehall347 is offline   Reply With Quote
Old 02-25-2021, 08:52 AM   #12
petehall347
Badcaps Veteran
 
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 2,679
Default Re: Help substituting avalanche diode

this looks like it ...
https://elektrotanya.com/hitachi_ct2.../download.html
petehall347 is offline   Reply With Quote
Old 02-25-2021, 12:06 PM   #13
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,978
Default Re: Help substituting avalanche diode

It is possible that the power supply started to output a higher voltage causing the flyback to operate at a higher voltage and break down, but it could be the flyback was just at its end of life. I picked that schematic because I could not find the actual one for your tv so I found a Mitsubishi tv that had a similar circuit.
The Hitachi chassis is totally different

Last edited by R_J; 02-25-2021 at 12:10 PM..
R_J is offline   Reply With Quote
Old 02-25-2021, 01:09 PM   #14
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 24,373
Default Re: Help substituting avalanche diode

not hard to find.
it's D907
Attached Files
File Type: pdf mitsubishi_ct-2040bm.pdf (1.26 MB, 7 views)
stj is offline   Reply With Quote
Old 02-26-2021, 12:08 AM   #15
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,993
Default Re: Help substituting avalanche diode

I would use P5KE120A TVS diode as a replacement.
redwire is offline   Reply With Quote
Old 02-26-2021, 09:40 PM   #16
sam_sam_sam
Badcaps Veteran
 
Join Date: Jul 2011
City & State: Sunny Jacksonville FL
My Country: USA
Line Voltage: 120 Volts 60 HZ
I'm a: Knowledge Seeker
Posts: 2,598
Default Re: Help substituting avalanche diode

Is there anything special about this type diode
__________________
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *


These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board

All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
sam_sam_sam is offline   Reply With Quote
Old 02-26-2021, 11:03 PM   #17
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,993
Default Re: Help substituting avalanche diode

It's got a misleading name "avalanche diode" and nominal 120V (130-155V) rating. So it's a zener (=avalanche mode) but the wide range of reverse voltage spec. and high surge capability 2A 100usec mean it's really a TVS diode.

In the TV circuit, I can't find the schematic again but it seems to be an overvoltage clamp for when the power supply puts out too much voltage.
If the STR fails or something else happens the rail can go too high and the TVS diode clams to protect something but it will cook and short if that stays true for a long time. I see main power like 115VDC go up too high due to a bad regulator and it damages other parts, flyback too if the x-ray protection does not trip.
redwire is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2021
Powered by vBulletin ®
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:34 AM.
Did you find this forum helpful?