+KylJoy Posted April 28, 2020 Share Posted April 28, 2020 Have you re-flowed the solder around the components? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 28, 2020 Author Share Posted April 28, 2020 Just now, KylJoy said: Have you re-flowed the solder around the components? Yah I did Quote Link to comment Share on other sites More sharing options...
+KylJoy Posted April 28, 2020 Share Posted April 28, 2020 If the system is on and you press on some components, not just tap, does the problem happen? Flexing the board might open a break in a trace. Also, if you have a cool-down spray, you can cool the components that are hot when the system exhibits its symptoms and see if the cooling recovers the system. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 28, 2020 Author Share Posted April 28, 2020 19 minutes ago, KylJoy said: If the system is on and you press on some components, not just tap, does the problem happen? Flexing the board might open a break in a trace. Also, if you have a cool-down spray, you can cool the components that are hot when the system exhibits its symptoms and see if the cooling recovers the system. I took out the HD7407P and it seams like the the transistors don't get as hot if it's put so I'm feeling its the problem Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 29, 2020 Share Posted April 29, 2020 While the 7407 is out, could you measure the voltage on both outer legs of each transistor? (black lead to ground in all cases). I'm curious what voltages you see. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 29, 2020 Author Share Posted April 29, 2020 4 hours ago, ChildOfCv said: While the 7407 is out, could you measure the voltage on both outer legs of each transistor? (black lead to ground in all cases). I'm curious what voltages you see. The one is 10.7 and the other one is 17.1 Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 29, 2020 Share Posted April 29, 2020 That's not good. The power supply should only be 16V. If it's 17.1 at that point, it's likely 20V or better at the supply. Could you check the voltage at TP4 on the power supply board? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 29, 2020 Author Share Posted April 29, 2020 2 minutes ago, ChildOfCv said: That's not good. The power supply should only be 16V. If it's 17.1 at that point, it's likely 20V or better at the supply. Could you check the voltage at TP4 on the power supply board? Witch is that one capacitor? The 2200uf one test the output? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 29, 2020 Share Posted April 29, 2020 Yeah looks like it's the 2200uF one. The other one that has the ground test point is 10,000uF. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 29, 2020 Author Share Posted April 29, 2020 5 minutes ago, ChildOfCv said: Yeah looks like it's the 2200uF one. The other one that has the ground test point is 10,000uF. So how should I go about testing it ? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 29, 2020 Author Share Posted April 29, 2020 I don't have anything other then a multi matter Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 29, 2020 Share Posted April 29, 2020 4 minutes ago, kevincondrick@gmail.com said: I don't have anything other then a multi matter Right. Red lead on the point labeled TP4 (looks like the + lead on the capacitor) and black lead on TP1 (the - lead of the other capacitor). DC voltage mode with the unit turned on. AC voltage mode readings might also be interesting. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 29, 2020 Author Share Posted April 29, 2020 Alright I'll try that tomorrow Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 30, 2020 Author Share Posted April 30, 2020 8 hours ago, ChildOfCv said: Right. Red lead on the point labeled TP4 (looks like the + lead on the capacitor) and black lead on TP1 (the - lead of the other capacitor). DC voltage mode with the unit turned on. AC voltage mode readings might also be interesting. Ok so I tested the cap and I get 20v Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 30, 2020 Share Posted April 30, 2020 6 hours ago, kevincondrick@gmail.com said: Ok so I tested the cap and I get 20v That seems too high. The service manual specifies that its absolute highest should be (unloaded) 19.2V. When loaded, it should be closer to 16V. It offers the following instructions: 1) Unplug the transformer power input plug from the power board. Then: Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 30, 2020 Author Share Posted April 30, 2020 So pins 1and 3 I got 9.1 v Pins 2 and 3 got 9.1 v Pins 4 and 5 got 17.2 v So that's all with the limits Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 30, 2020 Share Posted April 30, 2020 Hmmmm. Well, I guess you could check these 8 diodes on the power board in diode mode: Leave the transformer unplugged for the test. You should get a reading with the probes across each component, but only in one direction for each one. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 30, 2020 Author Share Posted April 30, 2020 Alright I have checked those and also the voltage on the that cap was like 23.1 today but I'll recheck the diodes I know the one diode was like 5.0 idk if that's good or not Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 30, 2020 Author Share Posted April 30, 2020 .51 on the one diode Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted April 30, 2020 Author Share Posted April 30, 2020 You think that it cold be the cap? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted April 30, 2020 Share Posted April 30, 2020 3 hours ago, kevincondrick@gmail.com said: Alright I have checked those and also the voltage on the that cap was like 23.1 today but I'll recheck the diodes I know the one diode was like 5.0 idk if that's good or not Which diode was that? And what mode was your meter in? It's rare to see one that looks for more than about 2V in diode mode, so they tend not to be good for measuring the rating of zener diodes. At best they can tell you if a diode blocks current one way and allows it the other way, and what the voltage drop in the allow direction is. If you're measuring it in continuity/resistance mode, then the reading won't be useful other than for "yes/no" answers. For a "load" test, do you happen to have 4 1K resistors? If so, bundle the 1st leg of each resistor together, then do the same for the other leg, so that it should be about 250 ohms total. Connect those across the smaller capacitor and unplug the logic board, but leave the transformer plugged in. Measure the voltage across the capacitor. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 1, 2020 Author Share Posted May 1, 2020 (edited) The second one right below the 2200 cap And I was just testing the diod in the diod test to see if it was reading both ways . Witch it wasn't. And in that message I ment .5 not 5. Also I don't have any resisters on hand One more thing I did was changed the one 100uf cap on there. Is it possible for this voltage regulator to be bad? Edited May 1, 2020 by kevincondrick@gmail.com Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 1, 2020 Author Share Posted May 1, 2020 Do you know what I can replace the voltage regulators with ? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 1, 2020 Share Posted May 1, 2020 The voltage regulators are standard ICs. One is a 7805 and the other is a 7812. But for this issue, they are irrelevant. One is the +5V output and the other is the +12V output. The +16V output is unregulated for the most part. It is tapped before the 7812. If it's not connected to the logic board, it will be close to 17.1*1.41V because there's nothing draining it. It relies on loading to bring its voltage within spec. So the resistor suggestion was to create the expected amount of loading to see if it would respond accordingly. You said you already tested all the diodes on the logic board too, right? Because the two+one that are connected to the transistors are supposed to be that load. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 1, 2020 Author Share Posted May 1, 2020 So what do you suggest I do now I don't have any diodes to replace them with but I can order some up if you think that would be the best to replace them. Quote Link to comment Share on other sites More sharing options...
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