Hardware

Macintosh LC – Leak check

My old Mac LC has a lot of sentimental value. My first Mac. The result of a major saving up exercise. Bought primarily for the final year of my Computer Science degree. I squeezed quite a long life out of it, with a DayStar accelerator card that I bought out in the States while attending the MacWorld Expo 1993 (and there is a story to that) but it has been in its original box for over 24 years.

I fully intend getting this machine going again, probably using a BlueSCSI or similar. But I had seen from the many retro-computing YouTubers varying levels of capacitor and battery leakage. So today was a quick inspection to see if it is similarly affected.

On first inspection, the battery looks ok. No sign of leakage, but quite flat, only able to deliver 41 mV as opposed to the 3.6V. If that’s a date code on the battery 11/89, I guess expecting any change remaining after 35 years was optimistic.

At a glance, there didn’t seem to be much problem near the caps. Although on closer inspection, it is clear that some of the component solder joints are matt with a green tinge – so, not so good. For now, I cleaned as best I can with isopropyl alcohol. The cotton swabs turning a horrible greenish colour kind of confirms the leakage. The board however does look in decent condition with the traces looking good.

Recapping is going to be vital I think before applying power back to the machine.

Additionally, it was also pretty sad to see how brown the casing had turned. It has spent a few years in a brightly sun-lit room before being boxed up, and is no-longer the nice light grey I remember. I’ll have to consider retro-brighting – but for me, this particular unit is a one-off. I don’t want to mess it up and I live in a flat – with no outdoor area for the sun part of the process, it is going to be a challenge.

Posted by creacog, 0 comments

iMac Fusion to SSD

Very long overdue. When I got hold of the iMac 5K, 27 inch, 2019, I was bargain hunting really. I like the large screen, I like that it was well discounted on the Apple Refurbished store, but I wasn’t over keen on the prospect of a fusion drive. Knowing that to replace it internally would mean removing the screen, I opted to wait until the warranty had expired. Far too long later, after suffering quite horrible slowness, and some system crashes (I am sure caused by the Fusion drive), it was time to do the switch.

As ever I researched via the many YouTube videos covering the subject, but opted for my own way.

First I got hold of the drive I intended to use (Crucial MX500 2TB SATA). This should do 560Mb/s. Not massively fast by today’s standards, but about 10* faster than the Fusion drive was achieving. A Sabrent ultra slim USB 3 enclosure was only around £10 so these two together, I essentially set the SSD up as a system drive:

  1. Format as a system drive – unfortunately it cannot be encrypted at this stage
  2. Install the system
  3. Turn on file vault – then migrating my home directory
  4. Use it as the system drive from now on

Immediately the speed increase is apparent. I used this configuration for a couple of months. However I really wanted rid of that fusion drive and bought the following parts, and with a free afternoon set about it.

  1. Sabrent 2.5″ SSD SATA to 3.5″ converter mounting kit
  2. iFixit Opening wheel
  3. OWC DIY bundle
    • In-line Digital Thermal Sensor
    • Glue strips

I am not convinced that the thermal sensor is strictly needed, but it would have been a real pain to find that it was having completed the instal.

The iFixit opening wheel felt flimsy, but did do the job, however it was nowhere near the quality of the iPhone 6s battery replacement kit. Once again, cleaning the residual glue from the frame was by far the most time-consuming aspect of this effort. But the most fiddly, and scary being the re-attachment of the screen cables far too short for my ‘ham fists’ to manipulate.

Having read some horror stories of the screen glue strips not being strong enough in some cases, I had opted for the well known OWC brand, rather than a much cheaper nameless product, and I also for the first 8 or 12 weeks used electrical tape to ensure there was no danger of the screen slipping off.

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Roland Alpha Juno 2 repair time

TLDR: I need to make the following repairs to my Roland Alpha Juno 2

  • Fix the touch sensitivity of one of the keys
  • Fix the non-sounding keys
  • Replace the back light
  • Replace the battery
  • Give it a good clean, inside and out

Using online articles and YouTube videos, I get into the repairs after sharing my history with this synth.

I saved up and bought it new in around 1986. I originally had a couple of small Casio keyboards PT-50 and MT-400V, and got my hands on a Roland SH-101 but wanted to step up to a polyphonic synth.

I was on a year out after my A-Levels, and earning, so a bus ride to into Manchester to hand over some cash (around £700 if i recall) and pick up my new Roland Alpha Juno 2. I’d never call myself a musician – I just enjoyed playing with the synthesis and trying to emulate the sounds of my favourite artists and bands of that time: Jean Michelle Jarre, Gary Numan, Ultravox, Human League, OMD and Pink Floyd.

I have always liked this synth and the feel of its semi-weighted keyboard and it seems to have lately found some popularity as a retro synth used by artists such as Kebu.

The synth (and home made amp) came with, as I left home in 1988 to study for my Computer Science degree. It survived the halls of residence and two student houses despite a near constant fear of being burgled.

In my first year however, it started behaving erratically and needed a repair. Rock city in Middlesborough did the repair job, which included replacement of the memory backup battery and some fuses. It hadn’t been again since. I’m amazed that the patches programmed over 30 years ago remain intact. Having owned it from new, I attach a lot of sentimental value to this synth and I don’t want to ruin it while I attempt to repair it.

I was able to find the reference materials on manualslib. Additionally I searched and found a number of repair videos on YouTube:

Saving the patches

Since I am going to change the battery, I need to dave the patch memory. To do that I used SysEx library on my Mac, and on the Juno, pressed simultaneously:

  • Data transfer
  • WRITE
  • Bulk

This sent 16 messages (4.2 Kb) to SysEx Library, which seems tiny by todays standards, but represents the 64 user defined patches.

Sysex of my Juno 2 user patches

Bad keys

First I marked the affected keys with tape:

  • The bottom C key, always plays 20% louder than other keys
  • The top D key, always plays 100% velocity, no matter how softly played
  • The middle G key does not sound
Alpha Juno 2 - Faulty keys labelled

Once inside, removing the keybed is a delicate and fiddly process – since the main board is slotted into the keybed. A rough hand could easily cause damage to that board. Ever careful to take photos of all the connectors in place, to provide reference for reassembly.

Alpha Juno 2, Opened
The main board sitting under, and slotted into the keybed.

The approach I took unscrew the board from the frame and slide it out, disconnecting the many connectors. Once the main board was free, I unscrewed the keybed from outside of the case and worked on it separately, away from the delicate electronics.

To get to the contacts we need to first remove the keys to which there are 3 stages:

  1. Remove the springs, keeping the shorter springs of the black keys separate from the larger springs for the white keys
  2. Underneath the keys, unstick and put aside the ‘Key Stoppers’ (clear plastic strips) that prevent the keys from slipping forwards.
  3. The keys will now pull forward and can be removed

Despite a good portion of its time boxed, thirty-odd years of dirt had certainly built up. With all the keys removed, all the dirt was brushed and vacuumed away, then the graphite pads of the affected keys cleaned. Removing the glue used to stick the key stoppers was the most time consuming effort.

All the keys went into a bucket of mildly soapy (washing up liquid) water for gentle but thorough cleaning before reassembly.

Backlight

In many of the restoration videos the LCD display is replaced with an LED display. I opted for replacing the electroluminescent strip with a new one. I managed to do this simply by desoldering the two connectors and slipping the strip out – without detaching the display from the frame.

Battery replacement

I opted to replace the soldered battery with a battery holder and standard CR3032. It was impressive that after over thirty years powering the memory for the user patches, the battery still held a good charge. Despite no liquid leakage, there was a white powdery coating building up on the battery.

Aftertouch

The remaining issue is that I have lost aftertouch. On testing the resistance of the aftertouch strip, I can see it changing with pressure. I hadn’t tested it before the disassembly, so this might have been an issue already rather than something I introduced. I may need to change the resistance range, but I haven’t yet worked out what that should be. One for the next project.

Conclusion

Aftertouch aside, I now have a clean, working Roland Alpha Juno 2. It makes a great MIDI controller for working with any DAW. But in some ways that is a waste for what is actually a decent synth from the late 80’s

Posted by creacog, 0 comments

My iPhone 6s battery replacement

My iPhone 6s is starting to show its age, with the battery barely lasting a day, and much less if actually used, it is time for a new phone or battery. The original plan being to do this ahead of my Christmas travels. A positive Covid test put paid to the Christmas travels, the kit was already on its way.

I opted for the iPhone 6s Battery kit from iFixit, containing the new battery and all the tools needed to make the replacement. Then followed their iPhone 6s Battery Replacement guide.

Possibly the most important instruction, and one that I think saved me from some trouble, is to discharge the existing battery before commencing the work. I then spent considerably longer than the suggested 45 minutes making this change. Reasons for spending so long:

  1. I only have this kit and no spare parts. Unlike a repair shop, if I break something I’d then have to order replacement parts and be without a phone over that period. I was particularly fearful of breaking the screen and spent an age gently warming with a hair dryer before gently releasing it from the frame.
  2. A surprising amount of dirt had found its way into the phone and needed a good clean up, along with the old glue strips from the screen on which I used a good amount of isopropyl alcohol to clear them up.
  3. The old battery peel-back strips both immediately tore, leaving the battery firmly fixed in place

I realised I had pierced the battery when it emitted a sweet pear-drop kind of smell. Fortunately it had little or no charge, and I think only the outer skin was pierced. Moving more quickly I finally pulled it out, sealed the tear in the battery skin with electrical tape, and placed it in an unsealed tin box for a number of days. Later taking it to a recycling facility and advising that the skin had been pierced as it was handed over.

The new battery lasts well and gives the phone a new lease of life.

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Adding a simple oscilloscope

In preparation for the repair work expected on the SH-101 in particular, I anticipate needing to see the output waveform. Only considering audio signals, so there is no need to sample high frequencies.

The JYETech DSO Shell kit with sample rates up to 200KHz should do the job, and was a decent inexpensive project to get back into the swing of my soldering skills. I did find my old 15 watt soldering iron inadequate for soldering the large BNC connector, and so got hold of a 25 watt Antex (good to see the same brand going strong) which did the job.

Markus Fuller does a decent walkthrough of building this DSO kit.

My own efforts…

DSO Shell kit and instructions

Used some tape to hold the screen down to stop it flapping about while still working on the boards.

DSO Sheen, screen and two buttons soldered

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Speaker repair

I have an old NAD-320 amp and pair of JBL Control 1G speakers attached to the TV, but hadn’t used them in a while. Trying out Netflix and finding Hans Zimmer Live in Prague, the TV speakers were certainly inadequate. But what an awful crackling sound from the JBLs. They were about 20 years old, but hadn’t had too much use. Taking off the grill, and the reason was clear…

The foam, around the main cone had gone crispy, cracked and started falling apart. Even 20 years on it is still possible to buy JBL Control 1 speakers new, but I didn’t want to dump these if they could be repaired.

There are a number of repair videos on youtube (search for “jbl control 1 foam repair kit”) and I found a kit on eBay (though the seller doesn’t appear to be there at the time of writing) consisting of replacement foam baffles and glue.

(edit 9/9/2020: A decent repair video published this year)

Armed with these and a screwdriver, I set about it. Taking photos before disconnecting anything to make sure I could reconnect properly…

Then it is time to get rid of the old foam, held in place by glue in addition to being clamped to the speaker case. Firm but delicate screwdriver action required, especially where the foam is glued to the cone…

Since the foam had denatured it was quite difficult to clean away from the metal frame.

Kicking myself when a slip of my scraper slightly damaged the left part of the cone – though not enough to go through, and not damaging performance in any detectable way.

That done, glue applied around the metal frame and to the back of the cone, and the new flexible foam pressed into place and reassemble…

End result – looking like speakers again, and more importantly sounding crisp and clear.

Posted by creacog, 0 comments

Hello iPhone

I dragged myself into the smartphone era in 2010 with a HTC Desire. After a number of years use, it is time for a change. In the end, I found the Desire quite slow, Flash compatibility wasn’t all that useful and being dependent on the Network to eventually deploy updates frustrating. So I am happy to move from Android to iPhone with a nice new iPhone 6s.

Hello iPhone 6s
Posted by creacog in Apple, 0 comments

Mac Pro Wake from sleep, restarts instead

A couple of weeks ago my Mac Pro (Early 2008) started failing to wake properly from sleep – basically it would boot from scratch rather than awaken.

PRAM zapped and all the usual stuff you see written across various forum. Then at the point of installing a replacement backup battery, I noticed a bright red light on one of the RAM risers.

Cutting a long story short, one of the RAM modules has failed. Checking the system profile, 4Gb of installed RAM is missing. The mac has wisely ignored the failing bank of RAM, but it would have been nicer if it had also alerted me to the fact prior to looking inside.

End result: physically removed the modules on the failing bank and now sleep/wakeup works as normal again. Fingers crossed the memory supplier will replace the failing package on their lifetime warranty.

(Update: August 2018, I should have updated this at the time, but Crucial sent a replacement module very quickly and that has worked without fault ever since – the machine is still in regular use at time of writing)

Posted by creacog in Apple, 2 comments

MacPro early 2008 video card dies

A couple of months ago, during a particularly busy period of work, I started to suffer some quite strange symptoms with my MacPro. Essentially, ‘sometimes’ if the system went to sleep, it was not possible to properly wake it up. It was apparent that the machine was starting up, but there was no video signal to either of the two monitors attached. One being an Apple 23 inch LCD. The other being an old CRT. The only way to get back to a working condition being to force-shutdown and restart the system.

My first suspect was one of the monitors – possibly the LCD. But trying them individually and swapping the connectors over made no difference.

The next suspect being the video card. Taking a look inside, there was a shocking amount of dust build up. I removed the card and gave it a good clean. Unfortunately this didn’t solve the problem. Over the next few weeks the occurrence increased in frequency to the point where one Sunday, after 7 or 8 reboots, it was time for more drastic action.

ATI Radeon HD 2600 XT

I had found a discussion on the Apple support site which echoed the symptoms and seemed to confirm the video card being at fault. My Mac was out of warranty and I needed it working for the next day and so trekked to the Regent Street Apple Store. Really busy store – the worse part was trying to get the attention of a member of staff. But then it was plain sailing. I explained the issue. While he suggested it might make sense to bring in the Mac to be checked – doing so would have been a real pain, run up cost and taken ages. I was pretty confident in my diagnosis. The only option available was an upgrade – which I was pretty happy with. From reading the rest of the support discussion I really didn’t want to replace like with like.

So, £300 lighter I trekked back home with a Apple Mini-DVI to DVI Adapter and a 512Mb ATI Radeon HD 4870. Very releived that the item was in-stock.

It dwarfs the old card, taking up two slots and full width. Installation was not too hard. The worst bit trying to connect the extra power cables to the mother-board.

ATI Radeon HD 4870

Closed the machine and restarted. The new card was picked up immediately. No installation of drivers required. Note: I had been a little worried that drivers may be required as I had previously considered upgrading to  an NVIDIA® GeForce® GTX 285, for which I read that it was vital to install the drivers prior to installing the card. Something difficult to achieve if the old card is dead!

Summing up – very happy so far with the new ATI Radeon HD 4870 which has been running faultless for the last couple of months, and looking forward to more software making user of the GPU, particularly from the likes of Adobe.

Posted by creacog in Apple, 2 comments

resurrected my tascam porta 05

(Update: 9/9/2020 – higher resolution images)

Tascam Porta 05

Tascam Porta 05

Decided to dig out my old Tascam Porta 05 ministudio in order to digitise some old 4-track recordings. But, found that the play heads seemed to be stuck in the forward position. Full symptoms and notes:

  • Power on ok
  • Impossible to insert a cassette due to the position of the heads
  • Can hear the motor (which turns all the time power is on – this is normal)
  • Motor responds correctly to the pitch control
  • Fast forward button works – spins the central right capstan
  • Rewind button works – spins the central left capstan
  • Tape heads in forwards position, but the rubber wheel in front of the stop button is not forward enough to press against the metal capstan
  • The metal capstan, which should normally be spinning all the time the machine is powered is not actually spinning
  • Pressing play or record buttons does nothing – the central capstans that would fit into the tape spindles do not turn

I did google around trying to find a solution. I did find a couple of people with the same problem, but no solution posted. I googled for the service manual with no result other than someone in the states selling on ebay for around $22. I wish companies like this would get their service manuals PDF’d and onto the web – shouldn’t be an issue for what is essentially obsolete equipment?

Anyway, with no solution available from the outside, I decided to take a quick look inside to see if there was anything obviously out of place. Getting inside is easy:

  1. Remove the 5 screws from the back panel
  2. Carefully part the two sides noting that:
    • The power on/off slider will likely drop out as it detaches from the internal control
    • all the other sliders remain with the top of the case – but some detach in the process from the underlying control which remains in the base.
    • In my case the forward position of the tape heads was preventing the sides from separating. Pressing them back by pressing the plastic between the erase and write heads made enough space.

Inside the Tascam Porta 05

Close-up showing heads fixed forward

With the sides parted, I then powered up and observed the mechanics when pressing the various control buttons. I couldn’t see anything obvious, but then noticed that underneath the controls is a flywheel attached to that capstan in-front of the stop button. The flywheel is belt-driven and was not spinning.

Nudging the fly-wheel with a cotton-bud.

Using a cotton bud, I gave it a few nudges, attempting to pushing it round in either direction. I was quite surprised  after a few attempts when the belt picked up and the flywheel turned under the power of the motor. At the same time the heads snapped back into the retracted position, and the play and record buttons now worked.

All that remained was to give it a good clean-out and reassemble. Taking care to align the Record function sliders with their underlying controls, and get the 5 screws back in, and I am back in action with kit that I thought was pretty cutting edge back in 1987.

Posted by creacog in Personal, Sounds, 65 comments