comparison: content/hp8662a.rst
content/hp8662a.rst
- changeset 100
- 3a4b9ec3c0b0
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- 891633961417
- child 115
- 6b6e13653348
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| 99:fd44150ec807 | 100:3a4b9ec3c0b0 |
|---|---|
| 159 replaced it with a brand new inductor I recently bought when I repaired an | 159 replaced it with a brand new inductor I recently bought when I repaired an |
| 160 old analog scope (Metrix OX734) for a friend of mine (I allways buy several | 160 old analog scope (Metrix OX734) for a friend of mine (I allways buy several |
| 161 more parts than I really need, when these are cheap, just in case; seems to | 161 more parts than I really need, when these are cheap, just in case; seems to |
| 162 be a good idea), | 162 be a good idea), |
| 163 | 163 |
| 164 .. image:: {filename}images/hp8662a/broken_choke.jpg | |
| 165 :class: image-process-large-photo | |
| 166 | |
| 167 .. image:: {filename}images/hp8662a/replacement_choke.jpg | |
| 168 :class: image-process-large-photo | |
| 169 | |
| 164 - there are 2 small 400mA fuses on the inverter board to protect the base of | 170 - there are 2 small 400mA fuses on the inverter board to protect the base of |
| 165 the 2 switching (bipolar!) transistors (first time I see the base of an NPN | 171 the 2 switching (bipolar!) transistors (first time I see the base of an NPN |
| 166 transistor protected by a fuse, but it's also the first time I repair a | 172 transistor protected by a fuse, but it's also the first time I repair a |
| 167 switching PSU which the main switching transistors are bipolar ones and not | 173 switching PSU which the main switching transistors are bipolar ones and not |
| 168 MOSFET or so). These are small BUSS GMW 4/10 (400mA) fuses, they look nice | 174 MOSFET or so). These are small BUSS GMW 4/10 (400mA) fuses, they look nice |
| 169 and so but are very expensive (and a bit hard to find): something like 15€ | 175 and so but are very expensive (and a bit hard to find): something like 15€ |
| 170 each. So for now, I've replaced it with a simple 5x20 glass fuse: not as | 176 each. So for now, I've replaced it with a simple 5x20 glass fuse: not as |
| 171 skookum but does the job for a few cents. | 177 skookum but does the job for a few cents. |
| 172 | 178 |
| 173 .. image:: {filename}images/hp8662a/broken_choke.jpg | 179 .. image:: {filename}images/hp8662a/fuse_replacement.jpeg |
| 174 :class: image-process-large-photo | 180 :class: image-process-large-photo |
| 181 | |
| 175 | 182 |
| 176 After these fixes, I reassembled the PSU and tried again: the result was quite | 183 After these fixes, I reassembled the PSU and tried again: the result was quite |
| 177 promising, but not a complete success: the PSU seemed to start, but very | 184 promising, but not a complete success: the PSU seemed to start, but very |
| 178 quickly stops itself with an error LED on: the overvoltage protection was | 185 quickly stops itself with an error LED on: the overvoltage protection was |
| 179 shuting down the power. | 186 shuting down the power. |
