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Fridge compresor not running - correct replacement relay?
Not sure if this would apply to a larder 'fridge, but a common refrigerator failure is in the self-defrost timer. It gets stuck in the defrost mode and power does not get to the compressor.- Ylli
- Post #4
- Forum: Sensors and Actuators
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Heathkit AR-15 sound problems
Could really be any of the active devices - could even be one of those capacitors. If you use freeze spray, try to spray only one part at a time, and give it a couple seconds to respond before going on to the next. -
Heathkit AR-15 sound problems
There are not that many active devices, would be a good idea to measure them all (E-B-C of all transistors). Why? All things drift/fail with age. Another thing you could try before replacing caps is to try using a freeze spray (or canned air upside down) to see if anything is thermally... -
Heathkit AR-15 sound problems
May very well be a capacitor, but do a voltage check first. Measure and compare with the schematic both when it is working well and when it is distorting. You may be getting a DC shift somewhere that is taking the amp out of its linear operating range. -
Comedy Thread
Wow, without cropping out that wet spot, it is really hard to NOT see the bin floating.- Ylli
- Post #327
- Forum: Off-Topic Members Lounge
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Heathkit AR-15 receiver - problem with multiplex circuit
Issue is the difference between the base and emitter voltage of the transistor. The B-E junction looks a bit like a diode, so there will be no base current until the B-E voltage reaches the 'threshold' of a silicon junction. That is typically 0.6 volts. So theoretically with a B-E voltage of... -
Heathkit AR-15 receiver - problem with multiplex circuit
I had asked you to measure between them not each to ground. Your new numbers makes 0.75 volts between them is is basically the same as you measured earlier. I would have expect3d at least a couple of volts, but that was only a guess. what you see may be normal. They are reasonable. The only... -
Heathkit AR-15 receiver - problem with multiplex circuit
No, that seems quite low. Is that with all the switches back in their 'normal' positions? I assume you had no problem with the adjustment instructions - that things responded as expected? For thoroughness, let's measure the voltages on the base, emitter and collector of Q410 and Q411 and... -
Searching for Solder
If you are only an occasional user, then this might be of interest. It's what I usually buy: https://www.amazon.com/gp/product/B00AVLM4SO/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1- Ylli
- Post #6
- Forum: General Electronics Discussion
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Heathkit AR-15 receiver - problem with multiplex circuit
Can you post page 132 of the manual? -
Heathkit AR-15 receiver - problem with multiplex circuit
The section of the adjustments you posted in ..1.pdf and ..2.pdf are the right adjustments. Have you gone through them in full? I don't quite understand why they have you detune L409, except perhaps to reduce the signal level in the following stages to allow better adjustments - but then I... -
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Technique Question
Well there's your problem :). Generally, because of surface tension, solder will want to flow away from any areas that it can not 'wet' - i.e. areas without conductor under it. If you want to make a bridge, it is generally easier if you use a larger diameter solder, get the solder to flow...- Ylli
- Post #5
- Forum: General Electronics Discussion
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Heathkit AR-15 receiver - problem with multiplex circuit
I would think measuring the voltage at TP2 would be part of the alignment instructions. Look for the section that talks about adjusting L409 and/or T402. Correct on those diodes. The 2700 pF cap failure was something that Peterdeco saw, not me. (I've never seen the insides of an AR-15... -
Heathkit AR-15 receiver - problem with multiplex circuit
This is a somewhat unusual MPX scheme. More common is a scheme where the 19 KHz pilot is filtered out, amplifier, frequency double, and the used to dem-mux the audio, in this case that regenerated 19 KHz is doubled and used to injection lock a 38 KHz oscillator. Composite audio comes in to... -
Heathkit AR-15 receiver - problem with multiplex circuit
I don't have a full manual, what 'choke' are you referring to? -
Frustrated
Yes he does, it is on the low side. Almost has to be component values or a bad 555, as the circuit looks OK.- Ylli
- Post #12
- Forum: General Electronics Discussion
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Akai Stereo Receiver AA-1175 (Problem - Won't turn on at all)
No, manuals on hifiengine are free. You do need to register, but they will not sell your email address or send any spam. I did pull the whole manual and have not found anything that shows where the fuses are. Most likely in the left rear corner by the power outlets and the power transformers. -
Akai Stereo Receiver AA-1175 (Problem - Won't turn on at all)
Don't know, I just pulled the schematic, not the whole manual. -
Akai Stereo Receiver AA-1175 (Problem - Won't turn on at all)
hifiengine has the schematic/manual online. https://www.hifiengine.com/manual_library/akai/aa-1175.shtml If the dial lights do not light, then either they are all bad or fuse F1-2 is blown. Also want to check F1-1. Of course, fuses usually do not blow for no reason, so the main problem is...