Spectrum +3 Sound Distortion Fix Bodge
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Spectrum +3 Sound Distortion Fix Bodge
I have just done the distortion sound fix mod on a +3 (https://spectrumforeveryone.com/technic ... pectrum-3/) and can safely say there is no longer any distortion. As there is no sound…
Well if I load Exolon and put the TV volume up to absolute max I can just hear the title music playing really faintly. So it is producing sound but only just.
I have double checked all the resistors and all are the correct values. I have also checked for solder splashes etc. and cannot see anything untoward.
There was sound (but distorted) before doing this…
I have done this a good few times before without incident.
I am wondering if I damaged TR5 while lifting the emitter to connect it to the resistor? Everything else seems fine. I don’t have a spare to replace it with unfortunately. Possibly a ZTX751 from here? https://www.retroleum.co.uk/zx-spectrum-transistors
Well if I load Exolon and put the TV volume up to absolute max I can just hear the title music playing really faintly. So it is producing sound but only just.
I have double checked all the resistors and all are the correct values. I have also checked for solder splashes etc. and cannot see anything untoward.
There was sound (but distorted) before doing this…
I have done this a good few times before without incident.
I am wondering if I damaged TR5 while lifting the emitter to connect it to the resistor? Everything else seems fine. I don’t have a spare to replace it with unfortunately. Possibly a ZTX751 from here? https://www.retroleum.co.uk/zx-spectrum-transistors
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
Well, progress of sorts.
I fitted a BC549C transistor in TR5 after it was suggested that would be a good replacement.
I now get audible music from Exolon at about 50% of volume. The beeper based sound effects are still very quiet however.
I fitted a BC549C transistor in TR5 after it was suggested that would be a good replacement.
I now get audible music from Exolon at about 50% of volume. The beeper based sound effects are still very quiet however.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
Here is the removed transistor:
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
I have fitted a new TR5 and it made no difference.
Back to the drawing board. Next step will probably be to repeat the sound fix and see if I messed up anywhere.
Back to the drawing board. Next step will probably be to repeat the sound fix and see if I messed up anywhere.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
- 1024MAK
- Posts: 5124
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: Spectrum +3 Sound Distortion Fix Bodge
When you say that you have “double checked all the resistors and all are the correct values”, was this by testing with a multimeter or reading the colour codes?
Are you using metal film types (normally have a light blue coloured body) or carbon film types (normally have a light brown or yellow/cream coloured body) resistors?
Apart from a multimeter, what test gear do you have? Do you have a battery powered audio amplifier?
Does the lack of volume affect all the audio outputs of just some?
Mark
Are you using metal film types (normally have a light blue coloured body) or carbon film types (normally have a light brown or yellow/cream coloured body) resistors?
Apart from a multimeter, what test gear do you have? Do you have a battery powered audio amplifier?
Does the lack of volume affect all the audio outputs of just some?
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
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- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
Thanks Mark.
The audio was fine, but distorted, before the so mod so it is something I have done.
I am using the carbon film type of resistor.
I have rechecked each resistor by taking a resistor out of the appropriate packet, checking it with a multimeter and then putting it next to the resistor I have fitted on the board.
I don’t have an audio amplifier, just a multimeter and logic probe.
I have only tested with Exolon and Manic Miner, both at max volume on my TV.
With Exolon I get quiet AY music and sound effects.
With Manic Miner I can’t really hear anything so I think the beeper is either extremely quiet or not producing audible sound.
The audio was fine, but distorted, before the so mod so it is something I have done.
I am using the carbon film type of resistor.
I have rechecked each resistor by taking a resistor out of the appropriate packet, checking it with a multimeter and then putting it next to the resistor I have fitted on the board.
I don’t have an audio amplifier, just a multimeter and logic probe.
I have only tested with Exolon and Manic Miner, both at max volume on my TV.
With Exolon I get quiet AY music and sound effects.
With Manic Miner I can’t really hear anything so I think the beeper is either extremely quiet or not producing audible sound.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
- 1024MAK
- Posts: 5124
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: Spectrum +3 Sound Distortion Fix Bodge
Not even a shoebox tape recorder that can be set up in audio monitor mode?Lardo Boffin wrote: ↑Sat May 28, 2022 12:58 pm I don’t have an audio amplifier, just a multimeter and logic probe.
Here is a simple BASIC program to test the bleeper:
Code: Select all
10 FOR a=10 TO 20
20 BEEP .5,a
30 NEXT a
40 GO TO 10
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
-
- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
Ah, I do have one of those I think. Not thinking outside the box.1024MAK wrote: ↑Sat Jun 04, 2022 11:51 amNot even a shoebox tape recorder that can be set up in audio monitor mode?Lardo Boffin wrote: ↑Sat May 28, 2022 12:58 pm I don’t have an audio amplifier, just a multimeter and logic probe.
Mark
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
-
- Posts: 2176
- Joined: Sat Nov 26, 2016 2:42 am
Re: Spectrum +3 Sound Distortion Fix Bodge
I have made use of the Sound In port of my trusty WHSmiths tape player and at about 25% volume I can hear your beep program.
Spurred on by this I loaded Manic Miner and can hear all of the music and sound effects. Obviously the sound quality is reflective of a 1980s cheap tape player but it is there none the less.
I also loaded Exolon and got the lovely intro music so it seems that all of the sounds are being produced but are now very, very quiet…
Thanks Mark! At least I don’t seem to have really killed anything.
Spurred on by this I loaded Manic Miner and can hear all of the music and sound effects. Obviously the sound quality is reflective of a 1980s cheap tape player but it is there none the less.
I also loaded Exolon and got the lovely intro music so it seems that all of the sounds are being produced but are now very, very quiet…
Thanks Mark! At least I don’t seem to have really killed anything.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Re: Spectrum +3 Sound Distortion Fix Bodge
I was looking at my 128 +2B and I noticed a mod I did some time ago, which was to lift the 3.5mm jack socket, cut the track that links the two contacts and run a wire down to by the memory chips.
I think the purpose of this was to allow a stereo signal though I can't remember much about doing it.
Your quiet sounds make me think you've only got one channel output instead of two.
I'm going to try the distortion fix on my +3, I wonder if I'll get the same problem!
I think the purpose of this was to allow a stereo signal though I can't remember much about doing it.
Your quiet sounds make me think you've only got one channel output instead of two.
I'm going to try the distortion fix on my +3, I wonder if I'll get the same problem!