Re: Technics SL-1200MK2 internal grounding
Both the turntable and mixer are 2-prong power. No earth, with the box-within-a-box double insulated symbols.
I must say, it sounds stunning, with dynamics and balance that put my cheap Numark CD players to shame, so there's a lot of 'if it ain't broke don't fix it', but at high volume, when I hold the headshell I can hear a faint crackle from my body static leaking into the output, which I assumed was because of the internal grounding.
MartinConnolly
Member
Last Activity: 03-18-2023, 12:51 AM
Joined: 02-27-2022
Location: Hoddesdon
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Re: Technics SL-1200MK2 internal grounding
I may have just answered this myself. The Stanton is supplied with threaded plastic spacers for the retaining screws, so it becomes electrically isolated from the headshell. I still don't see the point of the 'ground strap' on the back though.Leave a comment:
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Technics SL-1200MK2 internal grounding
I have recently bought a pair of 1988 Technics SL-1200 Mk2 DJ turntables. All original components inside and all still work!
But, they have been 'internally grounded' which is a common mod that some DJs do which removes the ground wire and just connects the turntable chassis to one of the sheilds on the RCA phono cables.
Now, Technics say this shouldn't be done because the outputs from a phono cartridge are balanced positives and negatives, not unbalanced signal plus ground.
So, I plan to remove this mod.
However, looking at the back of my chosen... -
Re: GNB 2100LP industrial battery charger
PS. Sorry the picture is rotated 90 degs anticlockwise. Turn it clockwise and it makes sense.Leave a comment:
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Re: GNB 2100LP industrial battery charger
Please ignore the previous pictures. They were of much older chargers which we are going to scrap. Anyway, this is the insides of the charger in question. It's much more modern and I can't see any fault with it.
Here's what I know...... The three phase power comes into an RFI board you can just see at the bottom right, under the visible board. The three lives come out at the top, black wires, and go into a three phase bridge rectifier. There's then some MOVs, a smoothing cap etc to provide DC. On the side of the heat sink running...Leave a comment:
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Re: GNB 2100LP industrial battery charger
Here are photos of the the insides, plus the circuit diagram stuck to the inside of the cabinet. You can see the 3-phase lives come in to a circuit breaker, then each go to their own huge transformer. The output from these goes into this strange metal contraption at the top. Coming out of this is the 48v DC positive and negative. The positive goes through a fuse, the negative through a strip of metal. What is this? It is marked '150A 60mV'. Finally, the negative cable going out is melted through. The positive looks scorched too.
Can...Leave a comment:
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GNB 2100LP industrial battery charger
I have two of these, both showing F06 error 'no output current'. They charge 48v banks of batteries in warehouse reach-trucks. I can find nothing on the net about this other than the manual says 'check the fuse, SCRs and connecting cable. I've checked the fuse and cables.
So, SCRs. What are they? Can anyone help? This is heavy electricals for me. It runs on 3 phase 240v power and looks scary! -
Re: AKG N-SOLIDTUBE tube condenser microphone
I hope I've worked our how to attach photos.
Here's the PCB after being removed and the MOVs removed. You can see the patching and scorching around the diodes....Leave a comment:
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Re: AKG N-SOLIDTUBE tube condenser microphone
Thanks for the replies. There are some good photos there. You can see the two high voltage 22uF 450V smoothing caps wired I think in parallel, the low voltage 1000uF 63V smoothing cap and the two 63V 47uF caps which I'm not sure of their purpose. There appears to be one voltage regulator on the low voltage side attached to a heatsink with a variable resistor to set it, which then controls the high voltage side with a pair of high voltage transistors wired in parallel. The one I repaired had already had the transformer replaced and the...Leave a comment:
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AKG N-SOLIDTUBE tube condenser microphone
I have found nothing on the net about this little doozie. A power supply and interface box for a studio microphone that uses a valve and condenser in the body to produce a 'warm' sound. Yeah right!
Any way, the box just keeps blowing its fuse. Replaced the MOVs and it made no difference. There's a high voltage and low voltage side coming out of the transformer. Its all conventional design, with no switching. Disconnected the high voltage side and the fuse doesn't blow, so.......
There's only five capacitors on the board, so I just replaced them all as it would be so cheap... -
Re: Panasonic SA-BT330 F61 and F76 error - *GOT IT FIXED*
Same fix worked for me too. SA-BT230 just clicking on then off. No error displayed. The C5798 cap is on the opposite side of the board to the heatsink. Replaced both and it all works fine now. I got a 330v shock from the smoothing cap, which seems to hold a charge for ever. Take care to discharge this with a 100k resistor before working on the board. Thanks a lot guys.Leave a comment:
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