Cambridge Audio A3i repairs and mods

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#162
jaycee said:
Its usually the heatsink that CA skimp on..

You could probably just replace the R-core with a standard toroid if you want to get it working. Alex suggested it should have been run from 25VAC windings originally I think.
Click to expand...

Thanks for this advice. But I want to have the same transformer model.

In which other Cambridge Audio amplifier model is the same R-Core transformer in use ??

The A3i isn't easy to find as used version.
 
#163
tiefbassuebertr,

We have been distributing Cambridge Audio since the second era of the brand and the only place I have seen this transformer used is in the A3i.
Would you like me to ask my contact at Cambridge Audio if the 240V power transformer is still available?

Regards,

Michel
 
#165
amp is singing again

Hello to all
thanks to the replies service manuals and prints that were so kindly sent to me the cambridge amp is working perfectly again

now for something completley different

does dont change the tyres if the motor isnt running mean
if it aint broke dont fix it
and if not then what does the tyre thing mean
because the amp was broken

anyway it seems i had quite a few dry solder/cracks and resoldering the points along with the amp being in protection mode caused the problems
thanks to all for the help
dont change the tyres mmm-i dont get that one at all
cheers from oz
 
#166
Michel said:
tiefbassuebertr,

We have been distributing Cambridge Audio since the second era of the brand and the only place I have seen this transformer used is in the A3i.
Would you like me to ask my contact at Cambridge Audio if the 240V power transformer is still available?

Regards,

Michel
Click to expand...
Yes, I am happy, if you can ask this for me. Cambridge Audio in UK don't send me their reply.
 
#171
I note that the linked manufacturer states a number of comparisons to EI transformer, -30%, -40% -40% -50% ref EI.

They also claim advantages over toroidal, but state no values for comparison.

Is this possibly a case of measurements not able to confirm R core advantage over toroid?
 
#172
Hello tiefbassuebertr,

Sorry for the delay.
Here is what my contact at Cambridge Audio wrote:

See if there are labels on the transformer

PY236 3200-000010-001 TRANSFORMER R-CORE-230V BSI STD A3i
NO STOCK
PY337 3200-139051-400 TRANSFORMER 230V R-CORE NC-13905TH A3i
20 pcs in HK

Cheers

Regards,

Michel
 
#173
tiefbassuebertr said:
Thank you for reply. Interesting to know. But are you sure? Have you found out this by open the insulation sleeving?

On the insulating label from transformer version of my A3i device I read at the end
"115 °C THERMAL FUSE FITTED"
- go to the first picture by post #152
Click to expand...

Hi all
Yes I removed the paper/plastic that covers the coils, in between the 2 coils is a small card where all the connections are made and there is nothing else there.
1 question to all A3i owners, does any of you guys have a A3i in bits ?
I'm looking for 2 of the small knops, some how I misplaced mine and now...
I will pay of course.
Back to the table I'm fixing a stubborn Cambridge Audio A5.

Ric
 
#174
The hottest part of a toroid will be the middle. The heat cannot flow any further in than the middle. The heat MUST flow out from the hottest part. That middle is likely to be somewhere inside the iron core. The temperature sensitive fuse is likely placed as close to middle as physically possible or between the primary and secondary windings.

It does virtually no good to place the thermally sensitive fuse on the outside, where the transformer is coolest.
 
#175
Well this is about the R-CORE transformer in the cambridge Audio A3i.
I only described what I have in my transformer and if you know the model you will see that there is no termal fuse anywhere on it.
All the connection are in a small square cardboard material: 2 wires going to the primary coils and 4 wires from the secundary going out.
If there was a T-fuse it would be in series with the 240V line and there is no fuse to be seen or connected anywhere.
About the location you are right it should be as close as posible to the core of the transformer but that doesn't happen very often and normally I see them between the primary and secundary windings or on the outside of the transformer.
About my previous question? Anyone ?

Ric
 
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