CHASE GPR4403 Laboratory Receiver Service manual PLEASE

[Dave Bullock]

A plea for HELP.
We have a CHASE GPR4403 laboratory test receiver displaying UNCAL on the
LCD.
The operators manual describes this message as relating to a RF or IF fault.
Trawling the web I find that CHASE have been taken over several times since
our receiver was manufactured and emails to the new owners draw a blank.
Surely there must be more than one (our) GPR4403 out there and someone MUST
have service data.
Is it you...or do you know a man who can help.
PLEASE help me repair our Radio Club's test receiver if you possible can.
Thanks in anticipation
Dave
Amateur Radio club of Nottingham.

[harry.be...@gmail.com]

Op donderdag 25 maart 2010 09:54:35 UTC+1 schreef Dave Bullock:

Dear Dave,

I have exactly the same problem with my Chase receiver, did you manage to fix this problem? Hope to hear from you.
Many thanks
Jim

[simonda...@gmail.com]

Hi guys,
Did you ever get your Chase radio working again?
Simon

[chris....@europe.com]

The problem with this units is they loose their Flash Erom memory, causing them to go into Un Calibrated state (Uncal), this is normally due the Main Batteries going Faulty or in a Non Rechargable state, being switcedh off and un charged for a long period of time, or the unit being taken apart by someone not realizing if the internal back up battery gets discounted or is forced flat it will cause eRom loss.

Chase went under years back, there were one or two companies that claimed they could fix or re Flash the Roms, but were either unsuccesfull or very expensive.

[Tony]

Looks like these threads are years old so this will probably never be read! I designed the receiver. There is no service manual, unless one was done after I left the company. The receiver was calibrated automatically by computer over the rs 232 port before the units were shipped. The calibration points were stored in eprom. Depending on the year of manufacture there was a backup battery or 1 farad cap as backup. As the original spec was 10 years receiver life most receivers have now probably died. The cal software ran on a BBC micro. Any programming info is long gone.

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For full context, visit https://www.electrondepot.com/repair/chase-gpr4403-laboratory-receiver-service-manual-please-29513-.htm

[John Robertson]

On 2023/07/06 2:30 p.m., Tony wrote:
> Looks like these threads are years old so this will probably never be
> read! I designed the receiver. There is no service manual, unless one
> was done after I left the company. The receiver was calibrated
> automatically by computer over the rs 232 port before the units were
> shipped. The calibration points were stored in eprom. Depending on the
> year of manufacture there was a backup battery or 1 farad cap as backup.
> As the original spec was 10 years receiver life most receivers have now
> probably died. The cal software ran on a BBC micro. Any programming info
> is long gone.
>

Talk about planned obsolescence!

So the receiver calibration might change over time and there is
absolutely no way to fix this as there is no calibration program left
anywhere. I/m assuming if anything was changed in the receiver that it
would then need calibration...

And people wonder why I like fixing electronic toys prior to the 2000s!
Stuff after 2000 is not nearly as fixable - too many one-off or customer
parts.

Then there is the question of who owns the device they bought. As an
example one brand of pinball games shuts the game down if it is operated
on 50 or 60 Hertz and that is different than the line frequency
(60/50Hz) that the game was originally set up for.

John :-#(#
--
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John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

[Three Jeeps]

This makes me wonder if this end state of calibration data vanishing after xx years was a design requirement (specified by who?) or a byproduct of the design approach taken (to increase machine flexibility? reduce parts count? etc.).