... /> But be careful: if the coil was damaged, this may be ...

Also, when it's fixed, bear in mind that 6A's in my experience are quieter than earlier issues - I have one that you would think the coil is bust as there's no noise even with the case off, but all voltages are there and it works fine :)

B

I love that coil buzz, brings back memories.

... fried due to the broken coil. Use a ZTX 650/1 ...

... some questions ab out that coil - does anybody have the ... , seems like a tapped coil with all turns going the ...
If anybody has this coil, I'd like to know ... that is Dreamscape's old coil, looks like one layer ... be possible to modify a coil former used in a ...

Also, is the coil used on early issue Sinclair ... packs the same as the coil used on the later version ... has been said, if the coil is rewound (with new enamelled ... .

Also if the coil and/or the transistors are ...

... on your video, the power coil tests passed mirroring the results ...

... didn't bother testing the coil pins since there isn't ...

Don't forget a new coil, can be got from [URL="http://www.dataserve-retro.co.uk/contents/en-uk/d7.html"]here[/URL].

B

... circuit (TR4, TR5 and the coil).
What I would do ...

... and connect a 220 uH coil between R62 and board. (improves ...

... have no buzz from the coil (sick Spectrums with bad voltage ... they don't make the coil resonate - a Spectrum should have ... joy:
3) Change the Coil and Tr4/Tr5 again.

... try is Tuukka's 220uH coil mod to filter the LM1889 ...

LM1889N chip draws how much current?

A 220uH coil rated for 130mA can be used?

[QUOTE=Renegade;790358]LM1889N chip draws how much current?[/QUOTE]
Typically 35mA, max 45mA
[QUOTE=Renegade;790358]A 220uH coil rated for 130mA can be used?[/QUOTE]I don't see why not.

[B][I]Mark[/I][/B]

Datasheet says 35 mA typical, so yes, a 130 mA coil will be fine.

If your coil has a dc resistance over 5 ohms, it might be good to reduce R62 accordingly so that the lm1889 supply voltage does not drop too much.


Tuukka

... try is Tuukka's 220uH coil mod to filter the LM1889 ... possible that the 220 uH coil can substitute entirely R62 instead ...

[QUOTE=Falco-F8L;790375]As a matter of fact, it is highly possible that the 220 uH coil can substitute entirely R62 instead of being in series with it.[/QUOTE]

That's very true! Hoping to see the results!


Tuukka

... have no buzz from the coil (sick Spectrums with bad voltage ... they don't make the coil resonate - a Spectrum should have ... joy:
3) Change the Coil and Tr4/Tr5 again.

TR4, TR5, a coil, a power socket, an sr10s05 regulator and some capacitors ordered... exciting! :D

... possible that the 220 uH coil can substitute entirely R62 ... R15 with a 220 uH coil. Now I measure 35 ... series with the 220 uH coil. Measurement on C45 goes ... then, that the 220 uH coil does not much.
< ... .

2) The coil dos not lower ripple. Will ...

... kHz from the TR4/TR5/coil switching circuit
[*]Various frequencies ... outputs from the TR4/TR5/coil switching circuit would also help ...

... new board has a quieter coil and also hasa proper Zilog ...

For me, the added coil did reduce ripple at LM1889 ...

... I install the transistors and coil? There don't appear to ...

... be sure.

The coil can only be installed one ...

... both, along with the new coil, power socket, capacitor for C47 ...

... , a burning smell appeared, the coil buzzing stopped and the speccy ...

... circuit (TR4, TR5 and the coil etc.).

Also with ... of TR4, TR5 and the coil. If TR4, TR5 or the ... coil is faulty, the -5V supply ...

... line that comes from the coil and goes into the regulators ...