Bridge rectifier specs - replacement/upgrade


Dave Peterson
 

Hi All!

I have a 5440 who's LV PS is dead, dead, dead. I'm going to do a large cap replacement, and would like to replace/upgrade the three bridge rectifiers as well.

I've already selected my replacement caps and have the appropriate adapters lined up.

I did some research on finding a replacement rectifier for a 465 152-0488-00, and found that these are commonly replaced with something like a KBP210*, where * is a variety of letters that seems to correspond to variations of current/voltage specs. For example, I've found this Mouser listing:

https://www.mouser.com/ProductDetail/621-KBP210G

I'm learning that in the 465 this particular rectifier is prone to failure. Presumably the original part was operating near its limits, and these newer parts exceed the operating conditions experienced in these scopes. This Tek part number is the same for one rectifier in the 5440 as well.

So far my selection process has been more qualitative than based on knowledgeable selection of specifications. I have two other rectifiers in the 5440, CR848 and CR875, which appear to have the same specs from the electrical parts list: 2.5A, 50v.

I presume these are the forward current and the reverse voltage breakdown requirements. A) is my interpretation correct, B) what are the opinions regarding other specs to consider, and what are appropriate increases in specs? Is forward voltage something to be concerned with, reverse current, surge current, etc.?

Thanks for any input you can provide.
Dave


Michael W. Lynch
 

Dave,

I have used these parts successfully in a 465 and 475 that had failed rectifiers: RS403GL for the 152-0556-00 and RG404GL for the 152-0488-00 These are 200V (140V RMS) and 400V (280V RMS) respectively. Both 4 Amp rated continuous current and 200A Surge current.

Link: https://www.mouser.com/ProductDetail/Micro-Commercial-Components-MCC/RS403GL-BP?qs=%2Fha2pyFadujS2YnhLvu0dlNmjSrIPflZkDGeHFgoIAM%3D

MOUSER normally stocks these, but is out of the 404 at the moment.



--
Michael Lynch
Dardanelle, AR


Mark Vincent
 


Harvey White
 

double the current, at least double the voltage.

Higher voltage ratings don't make a difference here, just adds some safety.

Current ratings can be important, so if possible double at least.  You may have to compromise depending on how the rectifier is mounted in the power supply.  Heat sinks can be good.

Harvey

On 5/21/2021 11:52 AM, Dave Peterson via groups.io wrote:
Hi All!

I have a 5440 who's LV PS is dead, dead, dead. I'm going to do a large cap replacement, and would like to replace/upgrade the three bridge rectifiers as well.

I've already selected my replacement caps and have the appropriate adapters lined up.

I did some research on finding a replacement rectifier for a 465 152-0488-00, and found that these are commonly replaced with something like a KBP210*, where * is a variety of letters that seems to correspond to variations of current/voltage specs. For example, I've found this Mouser listing:

https://www.mouser.com/ProductDetail/621-KBP210G

I'm learning that in the 465 this particular rectifier is prone to failure. Presumably the original part was operating near its limits, and these newer parts exceed the operating conditions experienced in these scopes. This Tek part number is the same for one rectifier in the 5440 as well.

So far my selection process has been more qualitative than based on knowledgeable selection of specifications. I have two other rectifiers in the 5440, CR848 and CR875, which appear to have the same specs from the electrical parts list: 2.5A, 50v.

I presume these are the forward current and the reverse voltage breakdown requirements. A) is my interpretation correct, B) what are the opinions regarding other specs to consider, and what are appropriate increases in specs? Is forward voltage something to be concerned with, reverse current, surge current, etc.?

Thanks for any input you can provide.
Dave





Dave Peterson
 

Thanks all for your inputs.
I need to become more familiar with the rectifier packages. I spent the afternoon tearing down the 5440 to get the PS out. I'm glad I did. One of the rectifiers is mounted to the rear of the body as a heat sink, and I wouldn't have been able to get a good look at it otherwise.
So I can tell that these three rectifiers all have different packages. The KBP210G is in a KBP package, but I don't know what the other two are. I'll have to do some more research. The lookup tool in Mouser seems to be one way to figure it out: KBP, KBU, GBU, etc. seem to be other varieties. Haven't hit a good web result yet either.

I'm inclined to replace only the 152-0488-00 as it seems to be a common failure part in Tek scopes. I see now that if this rectifier dies in the 5440 it will disable all the other supplies as it drives all the regulators. The 200v has it's own discrete diode rectifier, and that's the one supply that is working.
Dave

On Friday, May 21, 2021, 11:12:12 AM PDT, Harvey White <madyn@dragonworks.info> wrote:

double the current, at least double the voltage.

Higher voltage ratings don't make a difference here, just adds some safety.

Current ratings can be important, so if possible double at least.  You
may have to compromise depending on how the rectifier is mounted in the
power supply.  Heat sinks can be good.

Harvey


On 5/21/2021 11:52 AM, Dave Peterson via groups.io wrote:
Hi All!

I have a 5440 who's LV PS is dead, dead, dead. I'm going to do a large cap replacement, and would like to replace/upgrade the three bridge rectifiers as well.

I've already selected my replacement caps and have the appropriate adapters lined up.

I did some research on finding a replacement rectifier for a 465 152-0488-00, and found that these are commonly replaced with something like a KBP210*, where * is a variety of letters that seems to correspond to variations of current/voltage specs. For example, I've found this Mouser listing:

https://www.mouser.com/ProductDetail/621-KBP210G

I'm learning that in the 465 this particular rectifier is prone to failure. Presumably the original part was operating near its limits, and these newer parts exceed the operating conditions experienced in these scopes. This Tek part number is the same for one rectifier in the 5440 as well.

So far my selection process has been more qualitative than based on knowledgeable selection of specifications. I have two other rectifiers in the 5440, CR848 and CR875, which appear to have the same specs from the electrical parts list: 2.5A, 50v.

I presume these are the forward current and the reverse voltage breakdown requirements. A) is my interpretation correct, B) what are the opinions regarding other specs to consider, and what are appropriate increases in specs? Is forward voltage something to be concerned with, reverse current, surge current, etc.?

Thanks for any input you can provide.
Dave