- Vintage transistors and tin whiskers - 5 Updates
- USB Charging Module for 3.7V Lithium battery recommendation request - 1 Update
- 315M Laser fringe issues, help needed... - 1 Update
| Cursitor Doom <cd@not4mail.com>: May 19 05:43PM On Mon, 18 May 2020 05:43:18 -0700, abrsvc wrote: > may have been used to test something). Send me your address and I'll > send them along if you think that these will resolve your problem. I > doubt that I will ever use these. Thanks for the advice and offers of parts, guys; much appreciated. On reflection I decided to replace with silicon. The purists would go to the trouble of hollowing out the old transitors and fitting the silicons inside them. Fortunately, I'm no purist. :-D |
| Brian Gregory <void-invalid-dead-dontuse@gmail.com>: May 19 09:21PM +0100 On 18/05/2020 12:59, Adrian Tuddenham wrote: > I have had some success with an Eddystone EB35 by replacing them with > silicon transistors and adjusting the base bias to get approximately the > same collector current. And if something starts oscillating because you have too much gain with the silicon replacements then adding a low value R in series with their emitters will usually fix. -- Brian Gregory (in England). |
| abrsvc <dansabrservices@yahoo.com>: May 19 05:23PM -0700 On Tuesday, May 19, 2020 at 1:43:26 PM UTC-4, Cursitor Doom wrote: > reflection I decided to replace with silicon. The purists would go to the > trouble of hollowing out the old transitors and fitting the silicons > inside them. Fortunately, I'm no purist. :-D No problems here. If you want to use the ECGs to verify that everything works prior to "upgrading" to Si, the parts are available. These are small enough that they will fit into a small padded envelope, so shipping will be next to nothing. Let me know if you want them (no charge). Dan |
| Cursitor Doom <cd@not4mail.com>: May 20 12:42PM On Tue, 19 May 2020 17:23:37 -0700, abrsvc wrote: > shipping will be next to nothing. > Let me know if you want them (no charge). > Dan Thanks Dan, much appreciated. |
| adrian@poppyrecords.invalid.invalid (Adrian Tuddenham): May 20 03:40PM +0100 > And if something starts oscillating because you have too much gain with > the silicon replacements then adding a low value R in series with their > emitters will usually fix. There are already emitter resistors, but they are bypassed, so adding resistance in series with the bypass capacitors (or removing them altogether) would be the way to go. I used fairly mundane silicon transistors with a lowish cutoff frequency and didn't have any trouble. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
| Mike S <mscir@yahoo.com>: May 20 12:00AM -0700 I have a pair of Even h3 headphones that had a short to ground on the positive Voltage supply. The battery has a small circuit board attached to the terminals, similar battery ct's state "built-in battery protection circuit module PMC" for overcharging, overdischarging and short circuit protection. I think the circuit got stressed from being shorted to ground for too long too many times because the battery has 3.5 V after a short charge (connecting 4.5V directly to the terminals), but the output voltage from the circuit board is anywhere from 0 to 0.5Vdc. I'm looking at charging modules on ebay since this is a simple problem and cheaper than a battery, can anyone recommend a charger module they've had good luck with? These looks good to my inexperienced eye, but they're stated to be for an 18650 battery, I have a small flat battery, I don't know if this matters. high current (3A) version 5V USB 1S 3.7V Lipo Lithium Li-ion 18650 Battery Charging Board Charger Module https://www.ebay.com/itm/5V-USB-1S-3-7V-Lipo-Lithium-Li-ion-18650-Battery-Charging-Board-Charger-Module/191992007388?hash=item2cb39d8adc:m:mTJtSiEYqIJd4lTEvZWK95w lower current version USB 1S 3.7v 4.2v Lithium Lipo Li-ion 18650 Battery Charging Board Charger Module https://www.ebay.com/itm/USB-1S-3-7v-4-2v-Lithium-Lipo-Li-ion-18650-Battery-Charging-Board-Charger-Module/152734465560?epid=17006867994&hash=item238faefe18:g:NMQAAOSwvSxau44y My battery is similar to this, same 503040 battery but different ct. board. https://www.ebay.com/itm/503040-3-7v-Battery-600mAh-for-SkyBell-HD-Doorbell-Camera-Bluetooth-Headphones/193133417570 TIA Mike |
| Andrew Way <andrewwayconstruction@gmail.com>: May 19 11:36AM -0700 Hi there, I have a working 315M DPSS laser, with the controller, power supply, and a weird autostart dongle without the ready light... I am trying holography again (thanks Fred unterseher) in my livingroom with this new laser, but I think it may be having trouble stabilizing...? It starts up just fine, but when I run it though the interferometer it performs this "breathing" routine, where the fringe pattern moves a little in a regular manner every 3-4 seconds, contracting in. I have eliminated the possibility of table, pump, or fan movement- as my other cheapo chinesium diode laser settles just fine in no time. (I converted the 315M-100 to water cooling, but the weird fringe behavior persists even with the pump off for 15 mins). I have tried the recommendations in the laser faq for this model, DC voltage is good/stable, checked all ribbon cable conn's (visually, as i'd hate to brick it by poking around with a multimeter). I have also tried adjusting the pot down for a lower current/power setting to no avail- it resets and takes its 6mins to find a new stable setting, but the fringes never settle. I do not have a oscilloscope or power meter handy as of yet, but it seems to be stuck in a loop. Any suggestions would be appreciated! -Roo |
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