I knew that this might not to be the restful Saturday we had planned when my cell phone woke us just before 7:30 this morning.\u00a0 Klaus was already at the transmitter site trying to sort out multiple problems that were keeping TX2 from\u00a0 going on the air.\u00a0 He wanted me to come out to help.\u00a0 About 10 minutes later and just before I left, he called to say the transmitter was on the air and that we should plan on going out at 2pm this afternoon for further investigation as to what was happening.<\/p>\n
We harvested a few more nartjies (mandarins) this morning, but the rest still have some green on them.\u00a0 These will wait until next week.\u00a0 Virginia picked a few lemons that are turning yellow.\u00a0 I watered three small trees, which have been planted fairly recently.\u00a0 They are less than three feet tall and at least two are citrus trees.\u00a0 The bunch of bananas that we cut down on Wednesday has ripened only a little bit.\u00a0 As we have finished up the previous bunch, we hope these are ready in a couple more days.<\/p>\n
Klaus and I left for the transmitter site about 2:30.\u00a0 TX2 came up with no problem for testing, but the metering for RF Exciter Q3&Q4 currents was still showing the drifting up and down like last night.\u00a0 We investigated further and once again found these currents were actually steady.\u00a0 All the other metering points on the same card were steady and we could find no other similar anomalies.\u00a0 I examined the log of faults that occurred this morning and noted that door interlock faults seemed to be the fault most frequently shutting the transmitter down.\u00a0 Klaus had temporarily bypassed the door interlock this morning to get the transmitter back on the air.<\/p>\n
TX2 came up fine at 4pm for its first short Urdu transmission of the evening and was performing well, yet the ‘drifting’ remained.\u00a0 We continued to ‘scratch our heads’ as to what was happening.\u00a0 The transmitter was then off for about 30 minutes before the next longer transmission.\u00a0 So we looked at the computer screen with all the metering information to see if other readings showed a similar drifting.\u00a0 Only one was found, but it was drifting over a much smaller range and in the opposite direction of the drifting of Q3&Q4 currents.\u00a0 This one was the RF Exciter +24 volt supply voltage.<\/p>\n
Fortunately we decided to stay for TX2 to start the second transmission.\u00a0 Every time the high voltage vacuum contactor switched on, the door interlock light flashed and one or more of the optical arc detector lights came on.\u00a0 These were the same symptoms that the transmitter had this morning.\u00a0 We noted that +24 volts supplies the interlock string.\u00a0 Klaus quickly bypassed the door interlock like he did this morning, but the problem persisted.\u00a0 The arc detector supplies are +15 volt.<\/p>\n
Klaus decided to measure the voltage on the RF exciter supply when the contactor switched on and noticed a significant momentary drop in voltage.\u00a0 I suggested paralleling an additional capacitor across the one in the supply, so Klaus quickly found a 230 uf capacitor that he pressed against the terminals of the one that was already there.\u00a0 The transmitter switched on!\u00a0 Now we had another problem — could Klaus hold the capacitor like that for at least another 20 minutes!\u00a0 I managed to find some clip leads and we were able to replace Klaus by some strategic connecting of the clip leads.<\/p>\n
We discovered that the capacitor that was bad was 10,000 uf and the one paralleling it was only 230 uf, so we searched for a bigger one in the stockroom.\u00a0 The largest one that could be found was 5,000 uf, but we figured if 230 uf could help get the transmitter on the air that the larger one would work until a replacement could be ordered.\u00a0 Using clip leads, we connected the 5,ooo uf capacitor which promptly tripped the transmitter off, but we turned it back on immediately.\u00a0 We should have put a resistor in series with the capacitor to charge it up before connecting it.\u00a0 Not doing so, the voltage dropped momentarily when the capacitor initially charged.\u00a0 Maybe next time we’ll remember!<\/p>\n
We finally left the site at about 5:30pm with confidence that the problems had been solved, but I am still ‘scratching my head’ trying to figure out why the Q3&Q4 metering currents were drifting, while their actual currents were steady.\u00a0 Also, why were the optical arc detectors also triggering on, as they were on a 15 volt supply?\u00a0 These mysteries will have to wait until Monday, when the schematics can be reviewed some more.<\/p>\n
This evening we were able to watch Samuel and Henri playing on the beach via Skype and Angelique’s smart phone.\u00a0 They were at South Haven, Michigan for the day.\u00a0 Oh, the wonders of today’s technology!\u00a0 Later we got to talk to, and see, Allan and their children.\u00a0 We learned that Audrey’s Upward Soccer team was undefeated this year.\u00a0 Allan, Joyce and Mark were her team’s coaches.<\/p>\n","protected":false},"excerpt":{"rendered":"
I knew that this might not to be the restful Saturday we had planned when my cell phone woke us just before 7:30 this morning.\u00a0 Klaus was already at the transmitter site trying to sort out multiple problems that were keeping TX2 from\u00a0 going on the air.\u00a0 He wanted me to come out to help.\u00a0 […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_s2mail":"yes","footnotes":""},"categories":[5],"tags":[11,12],"class_list":["post-375","post","type-post","status-publish","format-standard","hentry","category-swaziland-2013","tag-11","tag-swaziland"],"_links":{"self":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/375","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=375"}],"version-history":[{"count":1,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/375\/revisions"}],"predecessor-version":[{"id":650,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/375\/revisions\/650"}],"wp:attachment":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}