Topics

TAS455 TAS465 SMPS 119-5024-00 (Astec AA18020) repair


Jon
 

Hi everyone,

I'm trying to save this 'scope from landfill after a previous owner connected it to 230V with the power supply switched to 110V ! It's the earlier model (pre S/N B020099) with the switchable Astec AA18020 power supply. I have two initial requests

1) C5 and C6 , VDR1 and VDR2 have been removed. Please could someone tell me what was originally fitted in these positions.
2) Does anyone have a schematic for this power supply ? It's omitted from the Tek 070-8524-02 service manual.

Many thanks,

Jon


Jon
 

Is there anyone out there with a TAS455 or TAS465 S/N below B020100 that could help me out by looking at their power supply pcb ?


 

On Sun, Aug 2, 2020 at 12:05 AM, Jon wrote:


Is there anyone out there with a TAS455 or TAS465 S/N below B020100 that could
help me out by looking at their power supply pcb
The caps are 220u / 250V
The VDR's have two rows, on top H S3 and below 1505

/Håkan


Jon
 

Håkan,

Thank you that's really helpful :) . I haven't been able to find a matching VDR / MOV , are there any symbols or a manufacturer's logo, anything on the other side or even just the colour of them which might help me narrow the search down ? A photo if possible would be great.

Many thanks,

Jon


 

On Wed, Aug 5, 2020 at 03:54 PM, Jon wrote:


are there any symbols or a manufacturer's logo, anything on the other side or
even just the colour
No logo or anything on the reverse side and they are red. Not much to take a picture of.
Both were originally covered by shrink tubing.

/Håkan


ron roetzer
 

Although I have no direct knowledge of this power supply, I have worked on a number of SMPS. A MOV will always fail short, since it's purpose is to protect the line side semiconductors from a voltage surge. The part should be replaced with a 300V rated MOV. Littlefuse supplies a wide variety of parts. Just find the correct size (physical) part and go from there. https://www.littelfuse.com/products/varistors/radial-leaded.aspx Available from all the normal online suppliers.