Hardware

18
Jun
2019

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
23
Oct
2015

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
09
Sep
2012

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
10
Dec
2009

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
14
Jul
2009

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