Author Topic: Traco TXL 60W PSU repair  (Read 125 times)

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Offline 1980s_john

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Traco TXL 60W PSU repair
« on: December 10, 2019, 07:37:45 pm »
Hi,
Here are my notes on repairing three of these units, luckily very simple fixes.

The first was a the Traco TXL 060-0533T, which has three outputs, V1 =+5V adjustable, V2 = +15V fixed and  V3 = -15V fixed. Fault was -15V output gave -1V and +15V output gave +6V, it has a single indicator LED which was not lit.

First saw that C37 (-15V smoothing capacitor) was bulged, replaced with 450uF 35V low ESR. This caused -15V output to become -6V, +15V still only +6V. Started to look at primary, unsoldered mains input capacitor (C5, 150uF 400V), measured at 60uF so replaced - no change.

Looked around for any other suspects, unsoldered C12 (47uF 50V) and found it was nearly shorted. Replaced and all outputs now OK, LED lit. Tested up to 1A load, very little voltage drop.

 I think C12 might be in the starter circuit but I don't have a schematic.

The second was another TXL 060-0533T, this had no outputs. The main 150uF 400V cap measured 100uF but I decided to leave it in. Again C12 and C37 measured very low, replacing just these two restored normal operation (only tested to 1A out on V2 and V3 only as that was all the application needs).

The third unit was a newer variant, TXL 060-0533TI, fault was LED came on then went out, no output voltages. This has the same voltage and power rating, but separate grounds for each of the three outputs. Also the spec says V1 has to have a load to allow V2 and V3 to be regulated, so I used a 10 ohm 10 watt resistor (not needed on the earlier units). Draws 0.5A @ 5V so barely warm.

Inside it looks very similar to the earlier unit, a few changes here and there (eg no obvious fuse), and easier to remove the heatsinks.

I checked the main 150uF 400V cap and this was only 75uF but I again I left it in. Only C12 measured very low, and replacing this one cap (with a 47uF 63V one) restored normal operation, with 1A on V2 and V3.

Regards,
John
 


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