Forum: Troubleshooting Audio Equipment
06-10-2022, 01:03 AM
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Replies: 154
Views: 12,435
Re: Mackie CR4 amplifier no sound
You are welcome, it can be an interesting learning experience - and, you may actually fix your speakers. :)
Yes, don't worry, the mains power is completely isolated. It goes through the cord, then...
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Forum: Troubleshooting Audio Equipment
06-08-2022, 05:20 PM
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Replies: 154
Views: 12,435
Re: Mackie CR4 amplifier no sound
The re-soldered diode looks fine, good job on that. Did you completely take out C39? In you image, it still soldered on.
The black area is the burned PCB where Z3 and Z4 are. They are 12V, but...
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Forum: Troubleshooting Audio Equipment
05-30-2022, 09:52 AM
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Replies: 154
Views: 12,435
Re: Mackie CR4 amplifier no sound
You see, the no sound occurs when to much voltage is being apply to the TDA7265 amplifier chip on Pin5 - which is the Play/Mute pin. When there is voltage difference betwen the input voltage and the...
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Forum: Troubleshooting Audio Equipment
05-30-2022, 09:42 AM
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Replies: 154
Views: 12,435
Re: Mackie CR4 amplifier no sound
Great! Like you said, you have nothing to lose - but, since the no sound issue with these CRx speakers is quite widespread, it is likely that you will be able to fix them. If you haven't done so...
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Forum: Troubleshooting Audio Equipment
05-30-2022, 12:56 AM
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Replies: 154
Views: 12,435
Re: Mackie CR4 amplifier no sound
Hello. Thank you for reading and finding this thread useful. Don't worry about not having experience, I was in the same shoes and have learned a lot from the people on this great forum. :)
Since...
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Forum: Troubleshooting Audio Equipment
03-16-2022, 03:26 PM
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Replies: 73
Views: 18,505
Re: Mackie CR4 monitors
Great work! I am glad my topic has helped you fix your Mackies. As all the good people here on this forum directed me towards me fixing mine. :)
Now, I haven't replaced all the capacitors like you...
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Forum: Troubleshooting Audio Equipment
01-12-2022, 05:36 AM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
OK, that sounds great. I didn't observe any overheating or bad voltages. I checked the line that powers the OKI chip, the voltage is about the same or slightly lower than it was with the original...
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Forum: Troubleshooting Audio Equipment
01-11-2022, 04:09 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
After a couple of hours of testing, I think this may turn out to be a good conversion. For reference, here are the previous readings with the original PT.
A for black (center tap)
C for one red...
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Forum: Troubleshooting Audio Equipment
01-06-2022, 10:33 AM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Here are the results. The replaced transformer provides ~0.2 lower voltage now that it is loaded than the original one did.
I used a replacement cable clip as the original one was broken.
I...
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Forum: Troubleshooting Audio Equipment
01-05-2022, 05:16 AM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Update:
I found a 230VAC transformer that outputs dual 5.5V, it arrived today. It is also shielded, so it could have come from some audio equipment, which is a plus (it's used, but in good shape)....
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Forum: Troubleshooting Audio Equipment
12-27-2021, 05:57 PM
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Replies: 65
Views: 4,293
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Forum: Troubleshooting Audio Equipment
12-27-2021, 05:02 PM
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Replies: 65
Views: 4,293
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Forum: Troubleshooting Audio Equipment
12-26-2021, 06:22 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Thanks. If that's the case, then teplacing it wil be "go to eBay and search", which would bring Chinese sellers whose pictures of the products are usually generic/stock, plus the 50 day long...
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Forum: Troubleshooting Audio Equipment
12-26-2021, 06:03 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Could the marking T6-13CH on the original mean something like Transformer, center tap 6V, total voltage 13V, CHina? :D Maybe it's a 6-0-7, but Sony marked the two output voltages on it. In that case,...
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Forum: Troubleshooting Audio Equipment
12-25-2021, 07:59 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
I will check with my multimeter. I followed the traces, black wire is A, red wires are C (half voltage) and D (full voltage). I see that black goes through a resistor to the first pin of the display...
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Forum: Troubleshooting Audio Equipment
12-25-2021, 03:05 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
It is small. Maybe 2.5x2.5x4cm roughly. The longest dimension is the base with holes for being fixed to the casing with two screws. Based on its small size, it is probably a 5W, 2x0.125A or so. I'm...
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Forum: Troubleshooting Audio Equipment
12-25-2021, 02:55 PM
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Replies: 65
Views: 4,293
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Forum: Troubleshooting Audio Equipment
12-25-2021, 02:35 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
I didn't know there is a heating element inside. A heater? :)
So, could a resistor be inserted between the center tap 6V output to drop the voltage to the required 5.2V?
I guess the output voltage...
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Forum: Troubleshooting Audio Equipment
12-24-2021, 05:11 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
So finding a suitable 220-240VAC transformer with that specific output will be next to impossible?
I found a 6-0-6 transformer which gives a total of 12V, so I hoped it would work. But it would be...
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Forum: Troubleshooting Audio Equipment
12-24-2021, 04:29 PM
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Replies: 65
Views: 4,293
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Forum: Troubleshooting Audio Equipment
12-24-2021, 12:19 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Here it is, assembled and functional. After 40 years, it works and looks great! :)
Thanks, everybody, for helping me out.
When there is an 80' music hit on a local radio station played through...
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Forum: Troubleshooting Audio Equipment
12-23-2021, 05:59 PM
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Replies: 65
Views: 4,293
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Forum: Troubleshooting Audio Equipment
12-23-2021, 03:30 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
New update. I desoldered Pin12 from the line, left Pin18 soldered, the clock remained in a messed up 12/24 hour mode and lagging.
Resoldered Pin12, unsoldered Pin18: it returned to normal 12 hour...
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Forum: Troubleshooting Audio Equipment
12-23-2021, 01:43 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
Pin12 should be the 12/24 hour pin according to schematics.
But pin18 has no designation, no explanation of it's supposed to do. However, on the PCB itself, the connection points between pin18 an...
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Forum: Troubleshooting Audio Equipment
12-23-2021, 01:13 PM
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Replies: 65
Views: 4,293
Re: Sony ICF-C12W Radio Clock schematics (power)
I did what you suggested and I got some weird results. The clock now seems to be running at normal speed, so I guess it switched to 50Hz counter (I'll have to do some more testing on that).
When I...
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