projects:repair:philips_pe1542_power_supply
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| projects:repair:philips_pe1542_power_supply [2013/02/13 23:51] – created admin | projects:repair:philips_pe1542_power_supply [2024/09/21 23:33] (current) – admin | ||
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| - | ====== Philips PE1542 Power Supply ====== | + | ====== Philips PE1542 Power Supply |
| The Philips PE 1542 is a power supply which consists of three adjustable outputs, linear regulating, non-switching type. For sensitive measurements where signal spectrum measurements are required, switching type power supplies are less suitable, because they generate small amounts of (harmonic) signal noise themselves. Linear regulators are therefore most suitable for such applications. The power supply is based around three modules with each having a traditional ua723c regulator IC. The specifications of the power supply are: | The Philips PE 1542 is a power supply which consists of three adjustable outputs, linear regulating, non-switching type. For sensitive measurements where signal spectrum measurements are required, switching type power supplies are less suitable, because they generate small amounts of (harmonic) signal noise themselves. Linear regulators are therefore most suitable for such applications. The power supply is based around three modules with each having a traditional ua723c regulator IC. The specifications of the power supply are: | ||
| * 2x 0-20v, 0-1A | * 2x 0-20v, 0-1A | ||
| * 1x 0-7v, 0-3A | * 1x 0-7v, 0-3A | ||
| - | * Each of the tree channels has a traditional galvanometer-based display, which shows either voltage or current. A switch determines which one of the two is displayed. | + | * Each of the three channels has a traditional galvanometer-based display, which shows either voltage or current. A switch determines which one of the two is displayed. |
| ==== Noise decoupling ===== | ==== Noise decoupling ===== | ||
| Line 12: | Line 12: | ||
| ==== Galvanometer issue ==== | ==== Galvanometer issue ==== | ||
| - | Recently, one of the channels of the power supply spontaneously stopped working. When wiggling slightly with the knobs, the reading would come back, but this did not last very long. My initial thoughts were this would be related to a bad solder somewhere or bad potentiometer. After opening the device and inspecting the circuit board I did not see something unusual. So I started measuring. The ua723c had correct power supply, produced a stable reference voltage as well. By chance I noticed, when I pressed somewhere on the circuit board, the reading would come back. After this I noticed that the output terminals were also fine and giving a stabilized voltage, regardless of the reading of the galvanometer. So then I discovered something was wrong with the galvanometer and not something else and focussed on this part. I looked on the circuit board and followed the copper traces which where going to the galvanometer and measured voltage levels. That looked fine, however a very strange thing I noticed was that the concerning | + | Recently, one of the channels of the power supply spontaneously stopped working. When wiggling slightly with the knobs, the reading would come back, but this did not last very long. My initial thoughts were this would be related to a bad solder somewhere or bad potentiometer. After opening the device and inspecting the circuit board I did not see something unusual. So I started measuring. The ua723c had correct power supply, produced a stable reference voltage as well. By chance I noticed, when I pressed somewhere on the circuit board, the reading would come back. After this I noticed that the output terminals were also fine and giving a stabilized voltage, regardless of the reading of the galvanometer. So then I discovered something was wrong with the galvanometer and not something else and focussed on this part. I looked on the circuit board and followed the copper traces which were going to the galvanometer and measured voltage levels. That looked fine, however a very strange thing I noticed was that one of the concerning |
| | {{ http:// | | {{ http:// | ||
| - | ^ Philips PE 1542 circuit board ^ Galvanometer bottom | + | ^ Philips PE 1542 circuit board ^ Galvanometer bottom |
| + | |||
| + | ==== Service/ | ||
| + | All 6 potentiometers to set voltage/ | ||
| + | * 3x Switch DPDT, ON-ON, C&K Components (Farnell: 143-7699 / Manufacturer Art. Nr. 1201M2S3CQE2) | ||
| + | * 6X POTENTIOMETER, | ||
| + | |||
| + | Unfortunately, | ||
| + | * Mount the 6 potentiometers on an aluminium L-profile, Mount the whole assembly on the front panel with two spacers. | ||
| + | * Mount each switch behind an existing switch, by removing the original contacts. Then cut a square hole at the back of the original plastic handle. By shortening the handle of the new switch, at will fit into the back of the old handle. Use a small test circuit board or similar and some threaded rod (Which I soldered to the metal casing of the original switch) and screws to mount the new switch. | ||
| + | * On the main PCB, increase the 6 holes for the potentiometers to a diameter of 12mm. The new potentiometers are too short and must be soldered using additional wires, as can be seen on the last picture below. | ||
| + | |||
| + | Below some pictures of the Philips PE 1542: | ||
| + | |||
| + | | {{ : | ||
| + | ^ back - I ^ back - II ^ Dupont connectors for connecting\\ switches to main board ^ | ||
| + | |||
| + | | {{ : | ||
| + | ^ front ^ PCB - I ^ PCB - II ^ | ||
| + | |||
projects/repair/philips_pe1542_power_supply.1360795901.txt.gz · Last modified: 2013/02/13 23:51 by admin
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