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Thanks dlucy! I've taken a picture of the orignal 2sd234s: I think the O is the gain code (70-140). The KSD526s I ordered were Y (120-240). I didn't realise when I ordered them, but I see these are the only ones Mouser stock anyway. The Y have a higher hfe, so they should be okay? It's not...

The QX-9900 looks really nice, but it's huge! Yes I already recapped the whole amp. I used WIMA MKS2 for C1 and C2 on AWH-005 and UPW for the rest of that board (I could change to UKL though if it will make a difference). On AWG-009 I used WIMA MKS2 for C7, C8 and C1, C2 and the rest UPW. For...

Hi F1nut, thanks for replying. It's very interesting. I wonder if it's any safer to have the chassis ground connected to the house earth? I was always told that applicances are safer when they are earthed, or at least double insulated. So you didn't need a new volume pot, just a motor...

Hi rcs It's great. And it's not that little. It's only 10watts, but it's the same size as the SA-9100, they look great together. I love the VU meters. I have no idea what's causing the problem. I could order both the TIP31A and MJE to try them both. What I noticed is that with the inputs from...

Wow looks really impressive! When you changed the power cable to the kettle plug socket, did you ground the earth pin? Do you have any more details about how you did the volume control? Suprised there's not more people doing this. Is it infrared?

Thanks zebulon! I can give them a try but I don't have anything else to order so I have to pay £12 delivery. And I had to pay that when I ordered the ksd526s.

Hi, Can anyone recommend which transistors to use to replace the 2sd234 output transitors on the power amp board in the QL-600a (AWH-005 - it's the same board in the SA-500a). I already tried ksd526 but these don't sound good. It's very distorted unless I turn the idle current up to around...

Hi everyone, My QL-600A has start making a loud crackling sound on the left (rear) channel after it's been on a while. About 6 months ago, I changed all the electrolytic capacitors and cleaned the controls and it had been working great. The noise isn't affected by any of the volume controls, so...

I put it into a voltage calculator on google and it came out as 0.02125 - I should have bought a 25 turn trimpot! You misspelt maths by the way :) Great! Thanks so much for your help with this. I'd no idea I should have been testing the collectors on Q11 and Q12.

Aha! This was the problem. I was on the DBT. On full power, pin 8 is about 41V. The schematics show 19.5V for the Q11 and Q12 collectors though. So should I set them to 19.5V, or half of pin 8 (around 20.5)? Either way, I can set the idle to 0.021V.

I don't know what B+ is? Is that pin 8? VR1 and VR2 are changing the voltage on the collector of Q11 and Q12. On the schematic, it shows the collector should be 19.5V. When I adjust VR1 so it's 19.5V, then I can no longer adjust VR3 to 25mV - highest it goes it 7mV. I did make a note of all...

Unfortunately I already replaced all 4 trimpots. I thought I measured all the pins before replacing, but I didn't see TP1 and TP2. Right now TP1 is 20mv and TP2 is 30mv, and adjusting VR3 and 4 changes the values, down to 0 all the way counter clockwise.

Hi, Does anyone know the procedure to set the idle current and offset for a QL600A? The power amp board has VR1-4 which I assume are for the alignment, but I don't know which pins to measure, and unfortunately there's no mention of it in the service manual. There are TP1 and TP2 pins and then...

Hey everyone, Thanks for the advice! It's taken 6 months, but I finally painted the letters back. I used enamel paint, and pretty much did exactly as restorer-john said. It's impossible to paint it into the groove perfectly, so I just rubbed the excess off afterwards with some isopropyl...

Yes they are engraved, sorry I didn't realise the picture isn't very clear. Can you recommend which kind of paint to use?

Hi everyone, I bought an SA-9100 a few months ago, in working condition, but needed a bit of the clean. I've just washed the faceplate in hot soapy water and some of the letters have come off! I guess the water must have been too hot, or I left it too long. I've found a couple of old threads...

Yes I think so. I really thought it would have been caused by a fault somewhere though.

Yes I've come to the conclusion it's just how it is. I've spent a couple of days with the receiver in pieces trying to see if I could get rid of all the crosstalk and noise. No luck, but I made some interesting discoveries: I found that when using the continuity test on my new DMM, if there is...

Hi Watthour, I already saw the switches on the schematic, and that S15 connects to ground. But if the input signal on aux is grounded, could it not be picked up somewhere else that is also connected to ground? I thought the same about the switches being the cause as it's affecting one channel...

I had a dig around today to see if I could figure out if the signal bleed was a problem or not. I unclipped all the cables and separated them out as best I could, and moved them away from the boards, but it made no difference. So I think I can rule out any issues with the cables. I've also...

I've noticed that the sound from one input can be heard on the other inputs when the volume is turned right up. For example, I had my phone connected to the Tape 1 inputs, and I left it playing when I flipped the tape 1 off and switched to Aux. When I turned the volume up I hear the music. I had...

I just tried this. I think I got it right because it has made a difference. I did two and put them in the Phono 1 inputs. I've attached a photo. I'd say the noise level is at least halved. Switching to Phono 2 is much louder. It's still not as quiet as the Aux input though (but almost). So...

Thanks - I am enjoying it :) I don't have a turntable yet, so I can't put a record on! I'm looking out for something like a Pioneer PL-570. But I get the idea, even with the volume turned just a quarter of the way round, it's very loud. It's crazy how loud it gets. I can give this a go. It...

It's been a few weeks since I had chance to get back to this. I put the BC550Cs back in, and tested the voltages with my new multimeter: Q1 - E: 28.7V (28.5) Q1 - C: 45.6V (47.5) Q1 - B: 29.1V (29.1) Q2 - E: 28.4V (28.5) Q2 - C: 45.6V (47.5) Q2 - B: 28.9V (29.1) I don't know what happened...

Thanks rcs16. I think what you're saying lines up with exactly what Watthour was saying a few posts ago. So I already tested the resistors, and they seem okay: R11: 215K (220) R43: 118K (120) R12: 220K (220) R44: 119K (120) R13: 12K (12) R14: 12K (12) I tested the old Q1/Q2 transistors and...